Category Archives: swimmin’ the chillies

Swimmin’ the chillies: It’s a thing. Really.

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I love swimming.

I’ve always been a distance swimmer at heart. I most enjoy marathon, swims of 10km or more, done following a few basic rules. I like that marathon swimming has parameters; I know them, I understand them, I can talk about them, use them to describe what I do and how I do it.

This past year I became a competitive cold water swimmer too, and now spend my days dreaming of swimmin’ the chillies as well. I do this with like-minded friends, a small chilly tribe, if you will. We may well all be nuts, but we’re pretty happy people, and love what we do.


Memphremagog Winter Swim Festival, March 2016. Me, second from far left.

As a newbie, I had a lot of questions, the parameters of swimming cold were unknown to me. Who governs this sport?  When does winter swimming begin, exactly? And how cold is “cold”, anyhow? Is it a thing, really? My brain needs to be able to shape things, to define, to categorize, it’s just how I’m wired…

Who dares swim the chillies?

It turns out a lot of people around the world swim in cold water. Here’s a few of my favourite examples:

  • Fall swimmers that continue past the summer, in cool/cold water. Some swimmers will set a goal to swim open water up to Halloween, and a fun new Vampire-themed swim series was established this year;
  • In Eastern Europe and Russia, Eastern Orthodox Christians celebrate the Epiphany by swimming in cold water. Typically, a hole in the shape of a cross is cut from the ice of lakes or rivers, and swimmers submerge three times to represent the Holy Trinity;
  • In Northern Europe, ice swimming is common after sauna as a way to cool off rapidly, a practice thought to boost health and relieve stress;
  • In various parts of the world, dousing is the practice of showering one’s body with ice water as a way to elevate internal temperature, doing so is thought to kill harmful bacteria and harden the body;
  • And of course, we can’t forget Polar Bear Plunges at Christmas or New Year’s Day to ring in the coming year. These are typically only short dips in the water, anywhere from a few seconds to a couple of minutes depending on the venue (and how risk-adverse your local authorities are, sigh Ottawa, sigh);
  • And finally, winter swimmers. Some swim for the simple joy of being outdoors, others train for formal events such as competitive winter races or ice miles. Cold water swimming is a cornerstone of training for any marathon or channel swimming taking place in colder climates.

Competitive winter swimming

I’m training to compete in cold water, and I also swim it for joy. I’ve addressed my joy elsewhere, so we’ll stick to talking about competitive swimming here.

Depending on where you are in the world, competitive cold swimming takes places in a variety of venues, here are links to a few examples:

Water temperature at competitions will typically be below 5C(41F), and as low or even below 0C(32F). You’re probably wondering how it’s possible for swimming to take place in 0C or below water temps. Wouldn’t it be frozen solid?

Many people assume that because water doesn’t appear frozen yet, it must be well above 0C(32F). Not necessarily so. If water has impurities, it may not freeze until below 0C(32F). Saltwater has an even lower freezing point of -2C(28.4F).

More importantly for our purposes, moving water won’t freeze at 0C(32F) either. When competitive swimming pools are cut from the ice on a river or lake, “bubblers” are placed just below the surface to purposefully keep the water moving so it doesn’t freeze back over.

And that’s how one swims at or below the freezing point. Brrrrr…..

Great video on the making of a cold competition pool – this ought to get you pumped!


Sanctioning cold water swims

Cold water swimming is not recognized by FINA (not yet, and not likely), as such there are no “official” rules or regulations governing its application worldwide.

So then how are competitive events sanctioned? Well, there are two “global organizations” to be aware of: the International Winter Swimming Association (IWSA, Finland), and the International Ice Swimming Association (IISA, South Africa). These are distinct groups, and are not related that I can tell except they both deal in different kinds of cold.

The IWSA’s mandate is to develop safe swim events in cold water worldwide. They have drafted formal rules and guidelines for cold water events, as well as identified categories of water coldness to help classify competitive events and the maximum race distances to be offered. Here’s a snapshot:

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My brain likes it when things fit into a chart. It’s good to have these kinds of parameters, it helps us talk about swimming in cold water, but I don’t know that we can call them “official”, per se. More on that in a sec.

In contrast, the IISA’s mandate is more narrow; to sanction both “ice mile” swims, which are 1-mile swims done in temperatures of 5C or below, and “ice zero” swims, same distance but swum at 1C or below. Some rules and guidelines are in place, but this is more of a recent addition. Very extreme, very dangerous. Some thoughts on it here.

Ok, so let’s come back to this, what’s the big deal about cold water swimming not having an “official” governing body? My view is this: as there is no one governing body that determines what “cold” or “ice” waters are, both are just a matter of interpretation. In fact, the IWSA determines “ice” to begin at 2C or below while the IISA declares an “ice” mile to be swum at 5C or below. IISA’s “ice” is a higher temperature and longer distance, but still, water temp is water temp. Different organizations, different pursuits.

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Cold water swims maybe not be FINA sanctioned, but both the ISWA and IISA do form their own competitive bodies, draft their own regulations, and sanction events under their own rules. But their ideas aren’t always the same, especially around things like requirements for emergency and safety support. It’s an evolving sport, and in North America a fairly new one at that, just something to keep in mind.

When does winter swimming actually start?

The IWSA declares winter swimming to start November 1st of each calendar year, but a fellow cold swimmie friend prefers to think of it as “when all the summer swimmers with good common sense stop showing up.”

Lacks definition, but I rather like that way of looking at things…

Happy swimming.


Physiological Responses to Cold Water Immersion

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I’m not a sciency person, but I’ve become passionate about a sport that requires any person performing it to understand at least the basics about what cold water does to the human body. There are risks associated with cold water swimming, and as with many sports, the greatest risk may well be that of ignorance. Knowledge is power, as the saying goes, and in our case, the biggest source of direction for swimming safely. Below are some key topics worth looking into further.

Kindly note, if you haven’t already done so – I’m not an expert on the science behind exposure to cold, or on the physiological risks associated with swimming in cold water. Anyone with existing medical conditions should absolutely consult medical experts if considering giving it a go, those with cardiac-related conditions should probably just find another sport to pursue, this one ain’t for you…

First stepping into cold water


For a lot of cold water swimmers, the experience starts before even stepping into the water. I get a little anxious, usually not for any particular reason: I know I’m safe, I know I’ve trained properly, I know I’ll love it once I’m in. But in the minutes preceding a swim, sometimes even on the drive to the waterfront, I get nervous, which naturally results in an elevated heart rate.

I’m learning to deal with it, I try to focus only on the tasks of arriving and setting up for the swim, I go through each step one at a time, mechanically. If I were worried about something serious, I’d rethink the swim, there’s always tomorrow. But otherwise I don’t let gitters derail my goals; if the idea of swimming in frigid temps isn’t enough to stop me from heading out to the beach, then I’m not sure as hell not going to let negative self-talk rob me of a good swim in its waters…

Thermal Touch

We’re on the shoreline, and about to step into the water, so let’s talk about thermal touch…

Thermal touch is the perception of temperature of objects in contact with the skin. To register cold, two completely different systems are functioning at the same time; sensation is the ability of sensory receptors in the skin to detect incoming information, whereas perception is the brain’s ability to take that incoming information and consciously determining it’s meaning.

The role of sensory receptors in this process is to register sensations related to objects the skin feels – in our case, skin registers the cold of water it’s being immersed in, or the chill of air that moves across it. Sensory receptors within our skin register contact with cold, and relay this information to the brain, which then translates it into meaningful thought. In moderately cool water, this may feel somewhat uncomfortable, whereas in very cold water it can be outright painful.

There are lots of different types of sensory receptors in the human body, which work together to relay information about the outside world to the brain. Here’s a couple of the most important ones that help us understand the sensations experienced in cold water swimming;

  • hot (heat) and cold thermoreceptors: located located in the dermis layer of the skin. There’s a much higher density of cold ones than hot, about three times more, with concentrations found especially in the face, ears, hands and feet. These receptors register radiant and conductive temperatures that would be considered harmless to the body; and
  • thermal nociceptors: located in the epidermis layer, those nociceptors responsive to noxious temperatures (= extreme hot or extreme cold) signal the central nervous system of imminent tissue damage and generate the impulse to withdraw the affected part from the thermal source. These receptors generate the sensation of pain, in very cold (ice) water swimming this would be the overall feeling of burning or stinging one gets across the surface of the skin, and after prolonged exposure, from ice crystal formation in the skin.


Temperature adaptation is another important concept for cold water swimming. This kind of adaptation occurs when the frequency of nerve impulses declines when stimulus remains constant. In simpler terms, a sensation may be strong at first, but then fades gradually as time passes. It’s one of the reasons why first getting into cold water may hurt or be uncomfortable, but within a few minutes I don’t really notice the cold against my skin nearly as much.

However, this adaptation doesn’t apply if conditions are too extreme. In very cold water, the sensation of cold is sensed by the nociceptors and registered by the brain as pain, and either lasts much longer or never fades off at all. Defining “very cold” is difficult, it varies by individual and by level of habituation to cold. Personally, I don’t feel this kind of sensory pain until below 6-5C(41-42.8F).

Cold thermoreceptors are most stimulated when the surface of the skin is below 25C(77F), and very importantly, stop being stimulated altogether below 5C(41C). In other words, if I’m in very cold water to the point that my skin temperature itself lowers to 5C(41C) or lower, I won’t register the cold at all as the thermoreceptors are no longer working – which means I will no longer be able to tell just how cold I’m getting based on the sensations coming from my skin. Nociceptors will still register the pain of cold, but I won’t be receiving any information specific to how cold, information I would otherwise use to ascertain how cold is affecting me. Dangerous territory, trained with great caution.

Now that I’ve painted a seemingly miserable picture of sensory pain, let me say that with practice, it’s not all that bad. I usually stand for a second or two in water up to my ankles, then walk right out to hip-deep water and stop to let my body/brain take it all in. When I’m ready, I drop down slowly to immerse my torso. In freezing cold water, this feels like a sensory explosion, every nerve firing, painful but completely alive.

Immersing the torso in cold water

Alrighty, we’re now waist-deep in the water…what happens next?

Mammalian diving reflex

The mammalian diving reflex is a reflex that optimizes respiration, so that mammals can stay under water for longer. It’s triggered by cold water making contact with the face. Once the reflex is activated, the following happens:

  1. Bradycardia: immediately upon the face’s contact with cold water, heart rate slows down 10-25%;
  2. Peripheral vasoconstriction (capillaries): capillaries in the extremities then start closing off, so that blood stops flowing in those areas, leaving more blood for vital organs to use. It starts with fingers and toes, then hands and feet, then arms and legs, and can result in cramping (especially in hands/feet) for some swimmers; and
  3. Blood shift: the excess blood is pushed into the thoracic organs, especially the lungs.

Many swimmers gently splash their faces when entering water, I do this when I’m standing waist-deep, just before dropping down to immerse my torso. The reason for this is to signal the vagus nerve, a cerebral nerve centre which transmits sensory information from the body to the brain, that cold is coming. The vagus nerve travels along the neck, like a superhighway connecting the body to the brain. Sudden shock to the vagus nerve can cause cardiac arrhythmia, so the splashing of water on the face gives your body time to register that it’s about to be immersed in cold water.

Capillary vasoconstriction:                     Vagus superhighway:

vaso                VagusNerve

Time to lower down and immerse my entire torso…

Cold shock response

Cold shock is the body’s response to sudden immersion in cold water, and lasts a minute or two, longer for some people. Once cold shock comes on, the following happens:

  1. Gasping reflex: rapid cooling of the skin causes an automatic gasping reflex;
  2. Hyperventilation: rapid breathing, also a natural response to the cold;
  3. Peripheral vasoconstriction (arteries): the arteries that carry blood away from the heart narrow, and the heart has to work harder to pump the same amount of blood throughout the body, resulting in an elevated heart rate.

Swimmers unaccustomed to the gasping reflex could be at risk of drowning if the gasp happens underwater and they take water into the lungs. When first learning to cold water swim, I always kept my head above water when getting in and let cold shock pas before swimming away. Now, as a more experienced cold swimmer, I have learned to swim through it – one has no choice in a racing environment, where swimmers enter water and start quickly (within 10-12 seconds), before cold shock has had a chance to pass.

Slow immersion into the water helps minimize the shock, but adaptation through repetition has been key in helping me manage cold shock. With continuous expose to cold through training swims, cold shock for me is now minimal at 7c(44.6F), it has to be much lower for cold shock to really come on strong.


The elevated heart rate is the true cause of concern, hence, seeing a medical doctor for advice before taking part in cold water swimming is wise. For people with underlying heart disease, it increases the chances of cardiac arrest, and general advice is to avoid cold water swimming altogether.

I recently wore my heart rate monitor during a training swim at 2.8C(37F), and forgot to stop my watch. The results were interesting, after an initial blip of high heart rate (160bpm), it took about 42 minutes to return to resting rate:

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Swimming about in cold water

After some time swimming around in the water, the muscles in my limbs become affected, something called cold incapacity. Understandably, muscles and nerve fibres don’t work well when cold. Neuromuscular activity slows and body fluids literally begin to congeal in the muscles. As a result, movement becomes increasingly difficult in hands and feet, then arms and legs.

With habituation, cold incapacity has become somewhat lessened, but you can’t outrun the cold. Eventually, it catches up with you. I’ve come out of the water with frozen hands and wobbly legs, but somehow my feet are little affected. I’m careful never to stay in so long that I can’t reasonably function when exiting the water, although in very cold water my hands get quite cold, and I often need help getting dressed. Thank goodness for support volunteers…

We’ve been out in the water for awhile, time to tackle the topic of hypothermia…

I struggle with writing about hypothermia; its such an important topic, and yet misunderstood by a lot of people, it’s hard to lay out the facts without sounding glib. But here’s my best efforts:

  • Fact 1: There’s no such thing as “sudden” hypothermia, hypothermia is a condition that develops over time. Sudden death in inexperienced cold water swimmers (i.e., fishermen that get thrown overboard) is most often the result of drowning by inhalation of water during cold shock, not sudden onset of hypothermia. One doesn’t “get” or “catch” hypothermia (like a cold), one develops it over time in exposure to cold. It can take up to 20-30 minutes for the average unacclimatized adult immersed in freezing waters to actually register a decrease in core temperature, and about another 20-30 minutes of useful consciousness left before severe hypothermia is likely to be reached.
  • Fact 2: Hypothermia, by definition, refers to low core body temperature. There are three levels of hypothermia: mild, moderate, severe. However, the core temperature ranges associated with each varies depending on the source, so we’ll follow suit with Loneswimmer’s approach and choose the higher of the scales.
    • normal body temp = 37C(99F)
    • mild: 36/37-35C (95F-89.7F)
    • medium: 34.9-32C (94.8-89.6F),
    • severe: 31.9-23.9C (89.5F-75F), leading to cardiac and respiratory failure
  • Fact 3: My opinion, the temperature ranges associated with each level of hypothermia matter little when in open water, unless you happen to be sporting a rectal thermometer somehow connected to a computer device that’s tracking core temp while you swim. Not likely. What does matter are knowing the risks and being able to identify the symptoms associated to each level, and learning to recognize them when swimming or supporting other swimmers. You can only achieve this knowledge through repeated practice, noting the effects of cold, and making wise training decisions accordingly.
  • Fact 4: In theory, some level of hypothermia is inevitable in water temperatures below body neutral 37C(98.6C). But the length of time it takes to become hypothermic varies with many factors, including level of acclimatization/adaptation, body mass and body fat index, water temperature,  air temps and wind speed. Ignore charts that assign specific water temps and times to the different levels of hypothermia – it’s a moving target, because it’s based on individual physiology and work done to adapt to cold.
  • Fact 5: Thinking you’ll be awesome overnight is a foolish approach to swimming in cold water, see facts 1-4. You can’t will yourself to be great, your confidence as an athlete and swimmer matters nothing to hypothermia, or to any of the other risks associated with cold water swimming. Cold will eventually catch up to you, so swim accordingly, and swim safe.
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Nope, not all in the mind, not at all…

Here are the basics symptoms for each level of hypothermia, best to consult expert resources for more in-depth information:

  1. Mild hypothermia: sensation of cool or cold, goosebumps, peripheral vasoconstriction ensues, dexterity of hands and feet may be reduced, but otherwise the swimmer is fine. Shivering may occur upon exit from water.
  2. Moderate hypothermia: blood thickens more, as such less oxygen to the brain results in thought process slowing or getting “cloudy”, resulting in mild confusion. As blood cools, bradycardia ensues (slow blood rate). Intense shivering occurs upon exit, and shivering may quite possibly occur while the swimmer is still in the water. Coordination slowed.
  3. Severe hypothermia: shivering stops, muscle coordination very poor, possible loss of awareness of others. “Paradoxical undressing” may occur, in which the muscles necessary for inducing vasoconstriction become exhausted and fail, causing warm blood to rush from the core to the extremities – the swimmer starts to feel warm again (on land, this may result in an individual taking off their clothing, further increasing the loss of heat, hence the term “undressing”). Towards the lower end of the temperature scale: pulmonary edina, cardiac and respiratory failure = death.

Most open water swimmers have experienced mild hypothermia at some point, but for cold water swimmers it’s usually a given. I’ve swum into the beginning stages of moderate hypothermia before, not on purpose, but it happens. I was in an outdoor pool at the time, with very cold ambient temperatures, I started shivering slightly each time I stopped at the wall – after a couple of laps, I realized the shivering wasn’t going to stop, so I exited immediately.

Well, I’m cold, but not too much so, but I’m ready to get out of the water, what’s next?

Getting out of the water

After-drop is a continued cooling of a person’s core temperature during the initial stages of rewarming from hypothermia. The “drop” in after-drop occurs when the blood that’s been cooling in our extremities starts to move through the body again, about 5-10 minutes after exit from the water.

Next to the initial point of entry into cold water, this has the potential to be the most dangerous time in the span of a cold swim – if a swimmer stays in too long, and the blood in their extremities gets too cold, when it starts to recirculate again it can result in a further drop in core temperature. The swimmer should be monitored after a swim, another reason I never swim alone. As part of my training, I’ve tested my thresholds for staying in cold and recovering afterwards very carefully, I don’t care to take unnecessary chances.

It’s also critical that swimmers not rewarm too quickly, so that the cold blood doesn’t move prematurely to the core. No hot showers or baths, gradual rewarming only. I dress quickly, before after-drop sets in, sip a hot beverage, walk along the beach.

Other things I’m careful of when swimming in cold water…

Exostosis (Surfer’s ear)

The most common cause of exostosis is frequent exposure to cold water: exposure to wind and cold water causes the bone surrounding the ear canal to thicken and constrict the ear canal, sometimes to the point of complete blockage (known as “occlusion”) which can lead to substantial conductive hearing loss. I wear earplugs.


Cold water entering the ear canal can cause disorientation, vertigo and nausea. Very unpleasant, and completely avoidable. Another reason for earplugs.

Frostbite (***warning: gross-out pics of my big toe below***)

Frostbite can occur in three different stages:

  • Frostnip is the first stage and a mild form of frostbite, which irritates the skin, causing redness and a cold feeling followed by numbness. Frostnip doesn’t permanently damage the skin, there’s no cellular damage.
  • Superficial frostbite is the second stage, reddened skin turns white or pale. This may be followed by burning, stinging, swelling and blisters in the coming 24-36 hours. Rewarming too quickly at this stage may cause skin to turn mottled, blue or purple.
  • Severe (deep) frostbite is the third stage, affecting even the tissues that lie below the skin. It is often accompanied by numbness, a loss of any sensation including pain, joints and muscles may no longer work. Large blisters for within 24-48 hours after rewarming, and the skin turns hard and dark as the tissue dies.

Frostnip can happen much more easily than most people realize, even in seemingly innocent water temps. At a recent swim while on visit in Hong Kong (you can read the details here), I swam for an hour in balmy 15.5C(59.9F) water, but the air was 3.4C(38.1F), but with wicked wind gusts up to 64km/h(37.8mph). I exited the water at the onset of moderate hypothermia, but more to the point, my feet got much colder than I realized, and I made the mistake of letting hot water run over my frozen toes as I waited to rewarm my body slowly in the shower. Frostnipped skin under the nail was affected, resulting in a bleed. As mentioned above, sudden rewarming is foolish as it encourages a deeper after-drop (I know this now, but not then), but the point being that the skin under both large toenails was damaged, a purple shadow at first, turning into a black patch, lasting months while slowly growing out. Lesson learned.


Cold skin cuts more easily. And because one’s skin gets numb, especially the feet, it’s possible to get deeper cuts without even realizing it. I’m very careful to watch the bottom while entering/exiting, looking for for sharp rocks, broken glass, jagged twigs. It’s another reason we stick to clean, sandy beach entry points wherever possible.

Swimming alone

It’s a foolish idea, no matter what the temperature. Besides, see how much happier we are when swimming with friends?


Adaptation to cold: habituation and acclimatization

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One needn’t be a special snowflake to swim in cold water, lots of different people do it. Some people might be more naturally skilled at it than others, but like any sport, it’s just as much learned and practiced.

When I first decide to keep swimming into the fall and winter, my goal was to continue enjoying the experience but also to push my level of adaption so that I could swim in much colder temperatures. Understanding the role of adaptation has come to play a huge part in the process…

Means of Adaptation to Cold

Three patterns of physiological cold adaptation are observed in humans: cold habituation, metabolic acclimatization, and insulative acclimatization. I’m going to throw in behavioural adaptation as well, as it’s important too.

1. Cold habituation

Cold habituation  is often described as the process of getting used to entering cold water, a sort of desensitization of thermal sensation to cold as a stressor on the body. In simpler terms, repeatedly getting into cold water gets easier over time, a swimmer’s skin and body adapts to the sensations of cold.

Entering cold water felt painful at first, like sharp pins and needles, but with habituation I’ve found it become more like a firing up of the senses, every single cold thermoreceptor under my skin ignited. It sparks the start of an intense sensory experience. The feeling of cold never really goes away, I always feel it, but I simply got more used to it, it started to matter less, and I seem to have learned to compartmentalize any discomfort.

Getting using to entering cold has some interesting side effects. As the body gets more used to entering cold water, this type of adaptation to cold “blunts”, or stops, both the shivering response and peripheral vasoconstriction (both discussed in detail here). There are two sides to this coin:

  • Positive side: blunted vasoconstriction allows the blood flow to remain moving regularly through a swimmer’s skin and extremities (in particular, hands and feet), without yet redirecting any significant amount of bloodflow to the core. As a result, skin and extremeties stay warmer longer, and the swimmer will likely maintain manual dexterity for a bit too. And, with shivering blunted as well, the swimmer likely has a higher level of physical comfort when exposed to cold or first entering cold water. With habituation, I’ve gotten to the point where I can stand around in the cold with much less discomfort than before or much notice given to cold.
  • Negative side: both shivering and vasoconstriction are critical in maintaining/creating warmth around the core. So while repeated exposure to cold might make getting into cold water feel easier, this blunting (stopping) of two keys heat mechanisms renders the swimmer’s core more susceptible to cold, and core temperature may start to drop at this point – before we’ve even gotten fully submerged in the water.

This is the reason most cold swimmers practice entering the water and submerging their bodies within a reasonable time, 1-2 minutes max. Competitive races are much faster, 10-20 seconds. Standing in the shallow end for 10-15 minutes trying to ease your way in will only result in a deeper drop in core temperature before the swim starts, which a swimmer will not likely be able to raise back up during the swim.

2. Insulative acclimatization

One of the very first responses the body has when entering cold water is typically peripheral vasoconstriction, at least to some degree, which simply put is when the body adjusts its pattern of blood circulation to redirect some of the blood flow away from extremities, and gather it around the body’s core to help create and insulate warmth.

The more significant the exposure to cold, or drop on core temperature, the more pronounced the vasoconstriction will be. The very first time I swam in cold water, back then “cold” was 12C, almost immediately I felt a surge of heat surrounding my core – the effects of vasoconstriction were quite pronounced. I was perfectly fine, although at the time I didn’t quite understand what was happening.

However, with repeated entry into cold water, the rate and severity at which peripheral vasoconstriction occurs has been greatly reduced. I can’t know for sure why without proper testing in a lab setting, but my theory is this:

  • I’m habituated to cold water, so vasoconstriction is blunted when I first get in. My hands are fine, my feet are fine, I don’t even shiver;
  • As I continue to swim, at some point my core temp drops enough to activate vasoconstriction, and some blood flow is moved away from my extremities towards my core. The colder I get, the more blood moves to my core. It takes me longer and longer to reach this point, which luckily means my hands don’t get as cold as they used to. I also believe this pattern to be true because I experience very minimal afterdrop coming out of most swims. Or, I’m playing it safer than I realize, hard to tell;
  • I can stay in cold water for quite some time, other mechanisms must be playing a significant role in keeping me warm enough to continue swimming…


3. Metabolic acclimatization

Enter metabolic acclimatization, also known as “thermogenesis”.

Heat loss is 25-30 times faster in water than air, due to conductive heat loss, which simply means the body continues to conduct heat to whatever the skin is in direct contact with – in this case, cold water (and likely cold air, if you’re still dallying in the shallow end). The colder the water, the quicker the body expels its heat. The body seeks to replace this heat by boosting metabolism or burning more calories to stay warm, which is the process of “thermogenesis”, the production of heat by the body.

Thermogenesis happens in two ways: shivering, and non-shivering.

Generally speaking, shivering is not a bad thing, even if it’s uncomfortable. It’s the body’s attempt to create heat; muscles contract quickly and as a result generate some warmth. Shivering comes on during exposure to cold, or even as a result of strenuous physical activity which results in a drop in core temperature. Even once a swim is over, shivering during after-drop means your body is working to heat back up. It’s also not uncommon for me to shiver or experience after-drop a little after strenuous training swims where I’ve given it my all, even in the warmth of summertime.

However, shivering while still swimming in water is something all together different, and is very dangerous – it’s a warning sign to get out immediately. Considering that heat is lost 25-30 times faster in water than air, shivering will only result in the opposite of it’s intention, and any heat produced by shivers will conduct away from the body much faster than if the swimmer were only exposed to air. Shivering in water is a last ditch effort to heat up, but will actually cause core temperature to continue dropping, and quickly. Shivering in the water means you’re done, swim’s over, there’s no recuperating lost heat, you need to get out and rewarm immediately.

The other type of thermogenesis is non-shivering, which is an area many cold water swimmers seek to improve and adapt.

The human body contains several types of fat, or adipose tissue, two of which play key roles in cold water swimming; white adipose tissue, and brown adipose tissue. White adipose tissue is distributed across the body, often in higher volume around the hips and stomach, it’s the fat many of us are most familiar with (I’m trying to lose a little as we speak). It acts as an insulator for the body to some extent, so that swimmers with a higher body fat mass may possibly be more able to stay in the water for longer periods.

But it’s not a general rule of thumb. White adipose tissue won’t do anything to generate heat. Brown adipose tissue (“brown fat”) on the other hand, will. Brown fat burns through stored energy at a high rate, in order to perform the very important job of generating heat – but without shivering, thus where the term “non-shivering thermogenesis” comes from. Both fats provide some insulation, but unlike white fat, blood flows through brown fat, essentially warming it up and transferring that heat to the body. And guess where brown fat gets its energy source from…white fat. Yep, brown fat is a fat-eating fat. How awesome is that.

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Babies are born with a fair amount of brown fat, since they cant shiver much yet, so it acts as a way to protect their small bodies. Until recently, it was thought that brown fat disappeared entirely into adulthood, but it’s been shown to not be the case, it’s only completely absent in some adults – most often, those who are overweight. To some extent, brown fat has been linked to leanness, as children with more brown fat have been shown to grow up to be leaner adults.

Brown fat sits more heavily around shoulders and the spinal cord in adults, and is more prevalent in women.

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It’s interesting, as we tend to assume people with higher overall body fat mass deal best with cold water swimming, and yet one of the keys to generating heat when exposed to cold has been linked to leanness. I happen to be short and a bit chubby, and love swimming in cold water, so it made sense to me at the time. As I’ve gotten to know the cold water community better, I realize now that I have swimmie friends of all shapes and sizes who swim at varying degrees of cold, even skinny minnies who’ve done ice miles. Body shape and size = not always a determinant of how well a swimmer will do in cold.

But here’s the really interesting thing: research has also shown that cold exposure to areas where brown fat is active can further stimulate its growth. In other words, an adult can increase the amount of brown fat they have, and consequently, increase the amount of heat they can generate when exposed to cold. And guess how. Yep. By getting into cold water often, exposure to cold helps generate more brown fat.

4. Behavioural adaptation

The behavioural changes have been very interesting to me. Bear in mind where I started from, I never could have imagined I’d be swimming in cold water:

  • a: I’m a big chicken
  • b: I complain constantly about being cold
  • c: I hate being uncomfortable


I often think back to my very first cold swim; I stayed in 12C water for about 60mins, I was the last one out, I wasn’t terribly cold afterwards, and I couldn’t wipe the grin off my face for hours. I was excited more than anything, that heightened sensory experience felt amazing, but I still had work to do in order to swim safely into colder waters. But there’s hope, even for big, cold, complainy chickens.

I seem to have developed a resolve and determination that wasn’t there before. Once I show up on shore for a cold swim, I’m set on doing it, no matter how hard it might be for me to get in the water. I always have some fear, some anxiety about it beforehand, I always tell myself this time will be the last one, it’s not for me, I hate cold. And each and every time, I overcome my negative self-talk. I get undressed, I get in, I end up loving it, I never want to get back out. It’s starting to translate to other areas of my life as well, which is really nice…

How often, how much?

Knowing a bit more about how the body can adapt to cold, the question for me remains as to how much training, what kinds of training, and how often would it take to keep adapting further?

There isn’t much research on the subject to really make a determination specific to cold water swimming, but there’s consensus on the following:

  • brief, intermittent exposure to cold produces seemingly negligible results
  • pronounced physiological adjustments come about only when repeated exposure to cold causes body heat loss, the kind of loss that can’t be recovered with metabolic heat production

So…apparently I’ve got to get cold to get better at being cold, and more often.

That’s fine, I figured as much. I’ll continue to play outdoors in the snow with puppy, I find it helps with habituation, and if I push it a bit longer, I can probably create some level of adaptation in the process. But I understand now why there’s skepticism about the effectiveness of cold showers or sitting outside in the snow as training methods. I mean, if it’s all you’ve got, use it, but it’s not likely for a swimmer to get cold enough to acclimatize, to effectuate any form of true physiological adaptation. Soaking in a tank or tub full of cold water in the backyard would be better.

Ice baths in the backyard. Cozy.

Practice is the hardest part of learning

I recently posted in a favourite swim forum about how eager I was to get back into cold water, for fear I’d lose some of my acclimatization. I was politely corrected by another swimmer, who insistent that someone fully “hardened” (= fully adapted) to cold never loses their acclimatization. They’d done all the research, they knew this for fact.

The comment didn’t sit well with me. I’ve always seen swimming as a learned and practiced activity; we learn the skills necessary to swim safely and swim well, and practice the sport to improve on our abilities. It’s not likely for us to unlearn these things, but more likely we could become out of practice at performing it. I don’t see why this doesn’t also apply to adaptation.

I was redirected to the swimmer’s personal swim blog, where I read an article they’d written with interest, but frankly, there was no evidence provided, just supposition and personal experience. Which is fine and well, but one person’s experience doesn’t apply to us all.

I turned to trusted resources, and learned there is research to show that when cold stimulus is removed, adaptation will gradually started to disappear. Some suggest a swimmer will lose adaptation 4-5 times faster than they gain it. And yet for other swimmers, the passing of time apparently seems to have little effect on their ability to get back into cold water. Am I one of those swimmers? Maybe. But I like learning, and value practising. Practice makes perfect, or something like that.

Friends: question everything you hear, which includes whatever I write here. I’m just one swimmer, no one can know it all, and some things you just have to learn for yourself…

Planning and supporting a cold swim

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Some element of planning goes into any swim, even if it’s as simple as packing up your gear, pouring a thermos of hot coffee or checking the weather forecast.

When we first started swimming in cool water (for us, about 10-15C), we didn’t put much effort into planning, it didn’t seem necessary. Everyone did their own thing; I brought along whatever I needed, and was able to dress and rewarm myself afterwards, no problem. We were more concerned with who would be bringing along the post-swim coffee and snacks. Very important detail.

As temperatures dropped below 10C and fall winds picked up, we noticed it was getting harder, especially post-swim. I forgot my flip-flops one day, and stood on bare rocks while changing; it took about 6 hours to fully regain the feeling in my feet. On one especially windy day, I lost all dexterity in my hands while standing on the shore chatting with fellow swimmers; I struggled to pull my bathing suit off, forget putting on bra and undies, I could barely pull up my own pants. On another blustery day, I was scolded for forgetting my wooly hat.

We realized then that if we were going to keep swimming progressively colder, we were going to have to put a bit more effort into planning. Otherwise I was sure to end up walking back to the car barefoot and half-naked, wrapped in only a towel (if I’d even remembered to bring it), trailing my kit bag behind me.


And so the planning began. For most swims, we were about 3-4 swimmers at any given time. Setting up on the beach was often a good time for friendly chatter:

  • What are your swim goals today? Are you here to simply enjoy the day, or do you have a specific goal you’re trying to achieve?
  • If you’ve got a goal in mind, what are you doing today to achieve it? Are you staying within your known thresholds, or are you going to be pushing any boundaries for the first time?
  • Anything we need to be aware of, anything we should watch out for on the swim?
  • What gear did you bring with you, what’s in your kit?

Whenever someone had an idea, or read something interesting, it would be shared with others by email or facebook. Ad nauseum, perhaps, but hey, it was an exciting time, we were learning new things.

Swimmers supporting swimmers

At a point, we realized we’d probably have to start helping each other more, especially dressing and rewarming after the swim. The colder it got, especially air and wind, the more frozen our little hands and feet got. We’d also started using a small tent on the shoreline, as the car was parked a good 10 minute walk away. At 7C, we could never know before the swim if we’d need help afterwards, so we went over the same questions each time just in case:

  • What are you doing today? [me: going for a bit more distance today]
  • How long are you staying in? [me: hopefully 20-25mins, depends on how I feel]
  • What do you need help with when you get out? [me: help me pull my suit off and get my first layer on, from there I’m good]
  • Where’s your stuff? [me: points to towel, thermal clothing and socks laid out in the corner of the tent]

When temps reached below 5C, questions got a little more serious:

  • Could we all agree to wear safety floats? (for visibility, and as a visual marker should something happen to the swimmer)
  • How would an extraction take place, if needed?
  • Who would call emergency services, if needed?

We actually started swimming one at a time, to ensure proper support could be given to anyone needing it. At below 5C, we weren’t in for more than a few minutes anyhow.

Back in the tent we laughed at each other’s lack of coordination, but a general rule of thumb emerged: there’s no shame in the tent. If a bathing suit wouldn’t come down, someone else would yank it down for you. If you couldn’t pull on your own underwear, someone else did it for you. Someone would even pull your wooly hat over your head, put on your mitts, and pour your hot tea, if you needed it. Having help takes a bit of getting used to, but no way were we sacrificing precious swim time for the convenience of being able to dress ourselves; swim your swim we said, someone else would help you afterwards if you needed it.

As much fun as swimming can be, doing it with a group – especially in frigid water – raised serious questions about groupthink and safety. It’s not wrong, or a personal attack on anyone, to ask yourself the following of your fellow swimmers (hopefully they are sizing you up as well):

  • Who are you swimming with, what experience do they have?
  • Do you trust them to be well prepared/informed?
  • Do they treat safety as seriously as you do?
  • Could anything they might do also put your safety or well-being at risk?
  • Are you expected to help them out, and if so, are you prepared for it?

I recently read an excerpt from a book that stated simply, “don’t swim with assholes”. Great advice. If you’re swimming together, and you can’t trust the people you’re with, best not to swim at all. You should be able to talk openly with your swim group about any concerns, and come to mutual agreements.

Dedicated support

We also became fortunate enough to have a friend volunteer her time to support our swims; we realize now it’s critical to have an extra person in extreme cold temps, someone who’s not planning to be in the water at all. Gen joined us at about 7C, and her help was especially invaluable in sub 5C swims.

Could fellow swimmers still support each other in sub 5C? Possibly, but the time it would take for the first swimmer to sufficiently recover to assist the second swimmer could be anywhere from 15-30minutes. On a windy shoreline, that’s enough time for the second swimmer to get quite cold before going in. Doable in a pinch, but perhaps not the wisest option.

The first time Gen supported for us, we sat in the tent and chatted about the swim beforehand. We went through my kit and pulled out everything she would need to help me with afterwards: towel, clothing, socks, hat, heat packs. We talked over the exit, and the order of things: towel dry torso, bathing suit off, sweater first, bottoms next, socks, gloves, cap off, hat on, heat packs under armpits.


With a lifeguarding and nursing background, not to mention numerous marathon swim accomplishments, we knew Gen was well suited to spot signs of trouble both during the swim and afterwards. We also came up with a method of signalling from the water – at each 50m loop of my swim, I paused for a quick moment, gave a thumbs up that things were a-ok in the water, and waited for a wave from the shore before continuing. Every once in awhile, I’d also swim up to shore, chat with Gen for a few seconds (her: tell me how you’re feeling), and kept going.

Another rule of thumb emerges: direction may come from the swimmer, but ultimately support is in charge. No different than a marathon or channel swim; the swimmer in the water often thinks they know best, but their judgment is easily impaired by cold and fatigue, so support and race officials have final say. They’ll see what you can’t. Gen says out, you’re out.

Luckily, we never had any issues. We were well organized, we recognized the risks involved and communicated well, and always swam within our individual thresholds. Whenever Gen noticed something off, she’d mention it, we’d think of a solution.

Supporting someone else’s swim, especially cold swims, carries responsibility. Even if your supporter doesn’t have Gen’s very ideal swim/lifesaving/nursing background, ultimately support are responsible for taking action if something goes wrong and the swimmer is incapacitated. They shouldn’t be uncomfortable with the following questions, as scary as they may seem:

  • Are these swimmers doing something stupid? Well, it’s a valid question. Perhaps better put as, are they well prepared for what they intend to do?
  • Will these swimmers respect my instruction? Where does the boundary lie between their goals and my expectations for their safety?
  • Do I know how to recognize signs of trouble, such as hypothermia? What’s the difference between a frozen tongue (hilarious) and slurred hypo speech (not funny at all)?
  • If something goes wrong, how will an extraction take place? Do I have the tools necessary to avoid possible injury to myself in doing so?
  • Will I know when to call in emergency services, and will I be able to explain our location on the beach/water?

We worked together to figure this stuff out. Once a basic plan was in place, we tabled the details and focused on enjoying our swims.

Supporting a swim is a thankless task, so be sure to let your supporter know how much you appreciate their time. Give them a hug or a high-five, bake them cookies, or pick up their coffee next time you’re out.

Scouting ideal cold swim locations

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When we first decided to continue swimming past the summer and into colder seasons, we really didn’t give much thought to location, instead returning each weekend to our usual swim haunt. Thinking back on it, the water was cool, but not yet cold – fall was late in coming, luckily warm air and sunny skies were still with us. Even as the temperature started to drop, it did so slowly, swimming was still business as usual.

I’m about to digress for quite some time before I get to the main point – either bear with me, or skip to the end if you get bored. But you shouldn’t, some important stuff right here:

Our usual swim spot is typically one of two beaches on Meech Lake, we head to either Blanchet Beach or O’Brien Beach. Located within a provincial park high up on the Gatineau Hills, the lake itself is choice for swimming: water is clean and sparkling, surrounded by tall majestic trees that turn shades of fiery orange in the fall, little fish swim about and occasionally a curious loon will come calling – or as in one day last summer, swim directly beneath me, heading in the opposite direction (to which I let out a startled scream underwater, but apparently, no one heard a thing). I have many cherished memories of swimming with friends here, of making new ones, being with nature, laughing, talking, eating cake and sipping coffee on the beach afterwards while savouring the satisfied tranquility that usually comes over me after a great swim.

There are many popular ways to swim the lake, two of which being to loop around the island off Blanchet Beach (800m) or swim a “beach-to-beach” (4km) from Blanchet down to O’Brien. Some swimmers do that last one twice, lovingly dubbed the “beach-to-beach-and-back” (8km). Swimmers of all sorts come here to work on open water skills: recreational swimmers, wild and open water swimmers, triathletes. Open water etiquette is well understood here by most – one is polite, one shares space at the picnic tables, one respects the water, the beach, other swimmers. One avoids collisions by swimming round the island counter-clockwise, NOT the other way, these rules are now tradition established by those who swim here regularly. And importantly, it feels very safe, with lifeguards watching the beach and several exit points along the shoreline should one need to walk back along the road. The water’s actually too calm to work on turbulence training or other more challenging environmental techniques, but otherwise it’s beautiful, serene, sunny, safe. It’s summer swimming, see you at 8am don’t be late, business as usual every weekend.

Which was part of the problem, to be frank. Those of us that swam on past the summer didn’t stop to consider if business as usual was still best under different circumstances. Fear not, dear reader, nothing went terribly wrong, but as the water and air temps cooled, the realization quickly set in that swimming cold has entirely different conditions, needs, risks. The big moment of consideration came on a brisk Saturday in October, air about 14C, water 12C, gentle breeze. To a hardened cold-water swimmer, 12C water is not really all that cold, but it was my first time at this temp, and I was still learning. It was also the first time water “felt” cold to me; I stood in the shallow end, hugging my torso and doing the silly bent knee shuffle one does when one wants to delay submersion. Brrrrr, water’s chilly, I thought, best head right on in. I fixed my goggles, marched in up to my neck, dove under quickly, and immediately pushed off to start my swim, ahead of the others. My stroke rate was wild, trying to rev up my core temp. We can talk about how stupid all that was here, but more important is what happened next.

Roughly 4 minutes later, and about 200 meters from shore, I was overtaken but a hot heat sensation across my chest and my breathing went short and hard. I stopped swimming and floated quietly in place, also realizing I was alone on the water. Shit, was this the onset of cardiac distress, I thought, shit, feels really weird. I rubbed at my chest wall, I wasn’t feeling any superficial pain, just a strange heat wrapped around the front of my torso. I waited for Gen to catch up, we chatted briefly, laughing about how chilly the water was and how nuts we were to be swimming in it. The sensation of heat remained with me, but a self-check in that moment revealed everything else was just fine, even my breathing had calmed. We swam off, I did 3 laps round the island (2400m), the sensation of heat lessened by the halfway point and was entire gone by the end of the third lap. I later learned that this had been my first time experiencing both cold shock (the body’s natural response to cooling of the skin, which includes gasping and laboured breathing) and significant peripheral vasoconstriction (circulation redirects some blood flow away from the extremities to the torso to protect vital organs, in my case, producing the sensation of heat). It’s possible – most likely, even – that my body had experienced these before but they were imperceptible to me, but at this point in my training, 12C was the threshold point that brought them on strong.

Here are the lessons learned that day:

  • I should have been better informed about what the cold could do to my body before actually swimming in it, there should have been no surprises, cold shock and peripheral vasoconstriction are both well-documented phenomena;
  • I should never have swum off without first (a) allowing cold shock to pass and (b) performing a self-check to weigh in on any concerns. I was too inexperienced at the time to predict and mitigate my own physiological responses to cold;
  • If I had been experiencing cardiac distress, or if I had accidently inhaled water into my lungs as a result of the gasping from cold shock, I likely would have been screwed, I was alone and possibly too far from shore to avoid drowning.

Sure, that last point about being careful is true of any open water swim, but these were physiological reactions specific to cold water. This can’t be stressed enough, cold impacts your body differently and brings with it other considerations. And that’s what got us really thinking about how to continue swimming cold but do so as safely as possible. If I had been screwed, it was early October, beach lifeguards and rescue equipment were long gone – how would an extraction from the water have taken place, would it have been faster to drive to a hospital or dial 911, and how far were we from any emergency services anyhow? We had no clue.

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The 23km route from the beach, out of the provincial park, and back to Ottawa.

So I mapped it out: 23km. We also realized that while Meech Lake is a lovely place to swim, getting there can be tricky; one has to drive slowly through the park along a narrow 2-lane roadway, being careful of cyclists and watchful for wildlife. As well, in the fall there are numerous events and festivals that draw cars and crowds. We decided accessibility was a critical consideration, and nixed Meech Lake as a late season cold-water venue. Over the next couple of months, we scouted other locations, ran into other issues, and finally settled on a small windsurfer’s cove off the Ottawa River.


We just have to keep an eye out for kite-surfers, fall seems to bring them out in hoards, but they’re pretty chill and we keep respectful distance from one another.

And so now I get to my point, at last. Here’s some of the things we took into consideration along the way:

Method/speed of entry into water

 Walking in from a shoreline: I definitely favour swimming locations that permit gradual and controlled entry into the water, especially in colder water, so typically sandy beaches. I find walking in gives my body a chance to adjust to the water/air temps, and I can fix my cap and adjust my goggles at the same time.

Walking down a boat launch: one venue we swam at was actually a boat launch, with a concrete ramp extending about 10 feet into the water. Seemed like a good idea, however we didn’t realize there were algae on the concrete’s surface towards the end of the ramp, causing me to slip and drop down quickly into 7C water. What started as slow entry ended in sudden submersion and heightened cold shock, and I struggled to catch my breath a bit during the swim. A supporter caught the moment on film, as well as my displeased reaction, in the pic on the right below.

Climbing down off a dock: I have also lowered myself down a rusty ladder off the side of a high dock, and at the ladder’s end had to drop off into the water below, quickly submerging my upper torso – the water temp was 8C, usually comfortable for me, but it took me awhile to catch my breath. I also felt a bit wary of relying on my arm strength to lower myself down, rather than very stable leg strength to walk in; it could be possible to lose one’s grip and fall in suddenly. In warmer water, probably not an issue, but in colder water it’s certainly not ideal. I would never consider actually jumping off the edge of a dock directly into cold water; I couldn’t possibly predict my body’s reaction to such sudden submersion – you’ve got to be a pretty seasoned cold water swimmer for that risk to be lessened. Although apparently local uni students idiots make a game of beer chasers and jumping on in off the dock. Why take the chance?

Most ice swim competitions require participants to quickly climb down a short ladder into the water, so training to submerge quickly is a goal I’m working to achieve. However, in very cold water I only want to practice this in a controlled manner – no rust, no algae, no dangling off the side of a dock.

Conditions of entry point

Obstructions: just as important as how one enters the water is the condition of the bottom they’re standing on or the shoreline on which they have to exit. Rocks, twigs or other obstructions play a significant role, especially upon exit from a very cold swim; my legs can sometimes get wobbly (at my first 2.8C swim, 3 minutes, I walked out like a drunken sailor), I certainly don’t want to trip over anything. Furthermore, cold skin cuts more easily and deeply, and if skin surface has numbed, it’s possible to injure oneself seriously without realizing the extent of damage. In moderately cool or cold temps, I’m less concerned, but when swimming in very cold water, I stick to sand or pebbled surfaces both in the water and on the beach.

Solid footing: in addition to finding a spot free of obstruction, I also look for a good, solid bottom – no mushy gunk. In more extreme cold temps (0-5C), I usually stay in shallow water no more than chest-deep, so that I can stand up at any time. When we swam off the cement boat launch, just after I slipped on the algae, I landed in about a foot of soft muck. I actually couldn’t gain solid footing, I had no choice but to push off and start swimming right away. Except I wasn’t quite ready yet, and no longer had control over my entry. And, if I’d needed to stop or to signal for help, I couldn’t be assured I’d be able to stand up very easily.


Depth of water: if the water’s too shallow, it takes much longer to enter and exit, which exposes me to air/wind conditions and may greatly amplify how cold I get overall. In the pics below, we tried out a beach that is really shallow for quite some ways, just look at how far away out I am from shore and I’m not even knee-deep in the water yet. That day air temp was -5C, water temp was 2.7C…I got colder exiting than I did on the swim itself. I also make a point of looking out for drop-off points on the bottom, so there are no sudden surprises.

Here’s a few other things we discuss when scouting new locations:

  • Visibility: can we swim about enough but still be seen easily from shore?
  • Extraction: are the conditions such that a supporter could pull you out without endangering themselves as well?
  • Accessibility in/out of venue: could an emergency vehicle make it in quickly? Could we make it back to the car in a rush?
  • Proximity to emergency services: we measured both time and distance to local emergency services (actual emergency, not walk-in clinics)

There’s no perfect spot, really. But we used the considerations above to make better choices, and this made us ready to mitigate any issues that could arise.

Overcautious? Unnecessary? If so, this probably isn’t the blog for you.

Swim safe!

Packing up a cold swim kit

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Aside the research done on cold swimming and location/support planning, developing a cold kit for training swims has been a most critical aspect of our swims. The things I pack into my own kit has changed over time; as water’s gotten colder, more issues and needs have surfaced. It looks like a lot, but once I figured out what worked for me, it’s just a simple matter of having a dedicated kit for cold swimming, ready to go at moment’s notice.

Gear for heading into the water

  • bathing suit: as weather gets colder, I switch to a slightly more worn and looser-fitting suit, so it’s easier for cold hands to pull off afterwards.
  • silicone cap: retains heat better than latex, sometimes I wear one of each for maximum heat retention.
  • earplugs: an absolute must for chilly swimmers in three critical ways, (1) retain more body heat, (2) prevent exostosis, and (3) avoid possible disorientation, vertigo and nausea caused by cold water entering the ear canal.
  • goggles: I use a pair dedicated to freshwater swimming as chlorine has a tendency to fog the lenses, and with mirrored or dark lenses if it’s sunny outside.
  • footwear: I wear crocs, but any plastic or waterproof footwear my feet easily slide into will do. As the shoreline gets colder/icier, I’m sure to wear something non-slip with good traction. I had to ditch my flip-flops for very cold swims because my exit is sometimes unsteady, not unlike a drunken sailor, and I wasted precious recovery time trying to fit the  little strap between my toes.
  • towel: It’s on the list because I tend to forget. Which really sucks.
  • thermometer: I always know both air and water temperatures, it allows me to both mentally prepare but more importantly gives me a baseline for what conditions and risks I’m exposing myself to before even getting in. Weather conditions make a huge difference on how cold I get and how well I recover, and how much help I may need upon exit.
  • watch: I always know how long I’ve been exposed to the cold, it helps me gauge my physiological condition during the swim. I use a GPS watch so I can track distance swum, but it’s not really necessary, key importance is keeping an eye on the time. I start the timer as I head in to the water, and also note the time of full torso submersion.
  • notepad and pen: I jot down the temps and times while we’re still on the beach, and record how the swim felt when I get home. If someone were just swimming for pleasure, this probably wouldn’t matter much, but I’m swimming to progressively habituate and acclimatize to cold, I like looking back at my progress over time and in various conditions.

Exiting the water in moderately cold temps, which for me = air and water about 7-9C:

  • sheltered way to change: in the absence of washroom/change room very nearby, the next best option is changing quickly on the beach. Men probably have it easier in this regard, a towel around the waist will do, but removing a woman’s one-piece suit and subsequently putting on clothing  while staying covered up is a bit trickier. Possibilities for all include an outdoor swim parka, a large poncho, or because I’m handy with a sewing machine making a longer version of something like this.
  • something to stand on while changing: flat kick board, yoga mat, extra towel, anything to keep my feet away from the cold ground and subsequently from getting even colder.
  • dry clothing: stretchy clothing is easier to put on, I wear layers where possible (better heat retention), warm socks are a must.
  • wooly hat and gloves/mitts: I keep my head and hands protected after a swim, to avoid losing more body heat. Gloves allow my hands more dexterity for getting dressed, whereas mitts have enough room to slide in a heat pack to warm those chilly fingers. I bring along a pair of each, and swap them out as needed.
  • something warm to drink: sweet tea, coffee and pea soup are my favourites, I’m not convinced either do much to warm my core, but drinking them feels nourishing.
  • kleenex: I get a runny nose. It’s not pretty. Trust me.

Exiting the water in very cold temps, which for me = air and water below 6C:

All of the above, plus…

  • swim float: it’s always a good idea to wear one no matter the temp, but we’ve made it a requirement for our more extreme cold swims.
  • hand towel: I now have the supporter gently dry and cover my hands immediately upon exit, before I even make it into the tent, to further prevent/limit nerve damage.
  • physical shelter to change in: I set up a small dome tent on the beach, or when it’s really windy, up on any grassy shoreline so I can stake in into the ground. It provides protection from cold and wind, and I can change quickly without fiddling under a swim parka. Unfortunately, our car is parked is too far away to get to quickly, otherwise the backseat would do just fine.
  • heat packs: my tent is too small to safely use a propane heater, but reusable Toasterz heat packs work like a charm (pic below), each pack is filled with food-grade fluid and a small metal disk, snapping the disk produces a chemical reaction that generates heat. Depending on the ambient temp and conditions, let’s use a light breezy 7C sunny day for example, the heat can last up to 45mins: first 10mins are hot heat, next 20mins are moderately warm heat, and afterwards a cozy lukewarm heat. In much colder temps, say 0-2C dark and windy, it will last about 10-15mins total. I have about 12 of them, just in case, and I keep them in a plastic container so they don’t accidentally activate while rolling around in my kit. I put on a base layer, then a tight vest or hoodie, and stuff the packs around my torso in between both fabric layers, positioned as one would do to rewarm a hypothermic patient.
  • other creative solutions for quick warming: inspired by a swimmie friend’s colourful onesie, which goes on quickly and is super-cozy, I bought one and made modifications to suit cold swimming; drawstring added to hood, pockets for heat packs sewn into torso area so the packs don’t slide around (I don’t always use the packs, but when I do, this helps), thermal socks sewn into the feet so the whole thing goes on in one fell swoop. Pics here.

The ideal kit for cold swimming will vary depending on any swimmer’s goals, needs, accessibility, air/water conditions, etc. Another example is fellow cold swimmer Michael Kenny‘s set-up, which is different than mine but works well for his swims. He lays everything out on a tarp on the beach, and brings along a chair to sit in while changing and a large sleeping bag for warmth/shelter, both great ideas.

Nope, not done yet…

  • my cold swimming gear is kept separate from my regular pool swimming stuff, as it often picks up sand and stones from the beach;
  • I pack my gear in a kit bag that has pockets for small stuff and a wide opening for bigger pieces, it’s easier to manage finding things beforehand and packing up afterwards in the cold, a big blue IKEA bag also does the trick when hands are too cold to roll up the tent properly;
  • I’m always checking out what other cold swimmers are doing, asking questions, asking for advice, exploring other ideas and solutions. I never stop learning, one person can’t know it all.

I try to bring along the positivity and confidence that comes from being informed and well-prepared. Being this prepared doesn’t stop me from enjoying the experience, besides, why am I there if I’m not having fun?

And I smile, it will (probably) only hurt for (hopefully) a little while!

To neoprene, or not to neoprene?

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Let me be frank. I don’t wear neoprene. Don’t take it personally, like many open water endurance swimmers, I pride myself on swimming by marathon/channel rules. But I don’t care what you do; if neoprene gets you in the water and helps you stay there, especially cold water, I say go for it. No wetsuit shaming here, though I do get a good chuckle sometimes when we notice differences between marathon/cold and triathlon swimmers:


Mick O’Kane, sometimes swimming skins is a strange and lonely place.

Mick took a lot of flack for posting that pic on a favourite swim forum, but I will say relative to cold water training, advice coming from triathlon forums/blogs at times takes a very different approach from marathon and cold water swimmers. It’s more common to refer to “handling” cold water or “making it more bearable” through the use of neoprene rather than learning to adapt to it without through repetitive habituation and acclimatization. I’m not making a sweeping generalization, some sites find a decent balance between both, but few explore the science or methodology behind physiological adaptation. And there are also lots of other reasons why most triathletes stick to wetsuits, racing advantages specifically, such as additional buoyancy and added glide through reduced surface friction. And well, not everyone cares to work on adaptation, some people simply hate the cold and neoprene is an easy way to stay warm. I say, why swim if you can’t be fully in nature with water, that’s half the joy. But hey, up to you, of course.

But even wearing a wetsuit, if you’re planning to swim in cool or cold water, you should still be working on adaptation: don’t let the wetsuit provide you with a false sense of security about your ability to “handle” cold. They aren’t a guarantee against getting cold, especially if you haven’t done any preparation. Suit up, get out there early on to practice being in cold, don’t wait until your swim to figure it out. You have other options too, apart from the wetsuit, such as neoprene skulls caps, gloves and booties (although if racing, check your event to see if these are permitted, they are not allowed at winter swim or ice events). For some people, wearing these along with a regular swim suit alone provide sufficient protection from the cold. Up to you, of course.

The point I want to make is this: if you’re looking to adapt and become better at swimming in cold water, neoprene or not, you might want to consider taking your advice from experienced cold water swimmers (great resource here). Even if you’re not planning a channel swim, or an ice mile, you’ll learn a lot from those who have dedicated themselves to the sport of swimming cold au naturel.

How do I know if neoprene is right for me?

Chances are if you’re still reading this post, you fall into the category of people looking to adapt to cold water, so here was my approach to figuring out if neoprene was needed as the season got colder:

  • I embraced that adaptation to cold water takes exposure and repetition, period;
  • The best time to start work on adaptation is at the end of the summer season, so that as the water gradually cools, you can continue swimming and safely testing your physiological limits;
  • If you regularly swim with a wetsuit during the summer, try ditching it, even if just for a bit (you might actually like it, just maybe). Go as long into the cold season as you can swimming ‘skins’, that is, without any neoprene at all;
  • As soon as you start to notice physiological or psychological impacts (i.e. chilling or slight numbing of extremities, decrease in amount of time you can comfortably swim, fear or anxiety about cold, etc), sit yourself down, turn inward, and have a good chat;
    • What exactly happened, what impact did the cold have on me? 
    • What are the possible consequences based on what happened, what are the risks to me? Could they be permanent, or am I likely to recuperate within a few hours/days/weeks? Note: careful on how you assess this, take advice first from experts on cold, which should include a medical doctor or nurse.
    • Should I continue with another swim to see if it happens again?
    • Can I find a way to minimize or mitigate the risk?
    • Am I willing to accept the consequences, if all else fails?

I can’t answer any of these questions for you, every swimmer must decide on their own where their threshold for risk and consequence lies. As I write this, a weirdly numb pea-sized spot on my thumb is still working it’s way bad to normal (not really numb, not really pain, just feels ‘weird’), three weeks after my last extreme cold swim at 0.6C. I knew this was a possibility going in, as it’s happened before with other similarly cold swims, so I’ve now added the extra step of having my hands dried and covered immediately upon exit from water to help limit nerve damage. With each cold swim my hands are better adapted, but there was always that risk. It’s up to you, of course, only you can decide what level of risk you’re willing to take.

The point is this: if you answer ‘no’ to that last question, no risk for you, but you still want to keep swimming in cold a bit longer past the summer season, consider using neoprene if it will assist you in doing so safely.

Let’s be very clear – neoprene will help keep your extremities warm, a skull cap in particular will help retain body heat. But if you are experiencing irregular heat rhythm, difficulties with blood pressure, disorientation, nausea and so forth, or have underlying health issues, diagnosed or otherwise, these symptoms and their consequences will most likely not be mitigated with the use of neoprene. See a doctor, get advice. Simply put, swimming past your threshold for cold might not be for you. No shame in that either, everyone is different.

But if you aren’t keen on risk, are looking to stay in longer than you normally would, or just want to keep your fingies and tippy-toes warm and well protected, here’s a few options:

Neoprene Gloves & Socks

Gloves come in both fingered and webbed options (on Diane, below). Apparently in some webbed gloves, the web can simply be cut out from between the fingers, although I’m told the webbing creates quite a workout (much like a swim paddle). Socks typically come up to a few inches above the ankle. About 3mm thickness is likely best, anything thicker and the buoyancy will throw off your swim technique. Very important: be sure you’re buying swimming-specific gloves and booties, and not those made for surfing or padding, the materials are quite different and the later are much heavier.

Neoprene Skull cap

Diane typically also wears a skull cap, quite excellent for limiting heat loss through the head. Find a style that fits you well, especially the strap, but you can also use a little body balm if you find the strap or sides chafe your skin. Again, be sure you’re buying a model that is intended for swimming.

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Neoprene Wetsuit

If you’ve never bought a wetsuit before, have one fitted at a professional shop, make sure the advice you’re getting is coming from experts. Or bring along a savvy triathlete friend. Swim shops may sell wetsuits, but the staff aren’t necessarily familiar with best fit or the benefits of various models and features. Fit matters; too loose and cold water will spill in quickly, too tight and the feeling of compression around your torso during cold shock will be amplified. Rent a wetsuit first, if you want to test out sizing in cold water before buying your own. Below, a pic of the one and only time I donned mine, bought for the sole purpose of extending my swimming season (and I do think it hugs my bum nicely). Who knew back then I wouldn’t be needing it after all…

Here’s Cary, another friend who came along for a swim in near-freezing 0.6C water, suited up in neoprene gear. She’s pouring warm water down her wetsuit before getting in:

Safe and happy cold swimming!