Cold water acclimatization

ChickenOSeaChickenOSea Charter Member
edited October 2020 in General Discussion
Hi all. I've been a regular in the cooler waters of Lake Michigan for a few years now but have not been coping with cooler water temperatures well at all lately.
Is it normal for people to go through phases like this? I've been completely checked out by my doctor and am fighting fit, but am getting very very cold and quite dizzy and tired after short swims at previously comfortable temperatures.

Am I just getting old? I cant tolerate the thought of not being able to swim in the lake.


  • loneswimmerloneswimmer IrelandCharter Member
    Are you sleeping ok? There is direct evidence that poor sleep or tiredness decreases cold tolerance (along with all the other stuff, alcohol, not eating enough, illness). (I was reading 2 research papers on it last, I might be able to find them again if you need).

  • ChickenOSeaChickenOSea Charter Member
    edited May 2012
    I'd love to see the papers you were reading, thanks. I have been wondering if this nasty phase is the result of a long period of stress and sporadic sleeplessness. Food and drink wise I'm good except I'm in the process of cutting back on caffeine just to see what happens (although I've always been a moderate coffee/tea drinker). This is all so strange. I feel ok in the water but experience a weird, unpleasant, sick kind of effect after short swims instead of the usual slightly shivery euphoria. Hopefully when the stress and exhaustion are under control, I will be too! Tx
    (also thinking of getting my hormones checked)
  • nvr2latenvr2late Central VirginiaCharter Member
    I have found that what Loneswimmer has stated, is true for me. If I go into a swim a little "off" or fatiqued, it is as if mentally, I am not prepared for the physical effects of the cold water. This happened to me just last week, and when I saw your note of concern, my response would have been similar to Loneswimmer. I hope that focusing on good quality sleep, and stress reduction, will improve your tolerance to cold. As far as hormones go, I think that my stage in life has been advantageous in that regard - I have just the right amount of body fat in all the right places, and I am HOT all the time. I think the polite phrase is "power surges" - I really enjy a brisk swim most of the time! I swam this morning in our lake and it was 72 - way to warm already here in Virginia - in a month it will be to hot in the lake!
  • slowmoslowmo Member
    What kind of temps have you been running into, I know the lake water by me can swing 4 or 5Ddegs in a day,maybe you are running into temp changes like that. I know if the water is in the 50f range my hunger goes off the charts when I'm done if the temp goes up by 7deg that doesn't happen.
  • Leonard_JansenLeonard_Jansen Charter Member
    Have you been checked for anemia? I was diagnosed with severe anemia (6.7 hematocrit count when 13 is normal for decrepit old men), bordering on life-threatening (=6.0), in January. I was having all kinds of weird problems for about a year, including a decrease in cold tolerance. After a few months of iron supplements (and an endlessly upset stomach) I am almost up to normal levels and feel better than James Brown.


    “Moderation is a fatal thing. Nothing succeeds like excess.” - Oscar Wilde

  • loneswimmerloneswimmer IrelandCharter Member
    edited May 2012
    @ChickenOSea, of course, now that I'm looking for them, (I was trying to understand fatigue last week and came across it only tangentially), I'm having problems finding them, I can't remember the keywords. I thought it was on Pubmed. Here's what I have so far, mostly abstracts only, but while they are indicative, they're not the ones I came across last week.

    Here is "Cold thermoregulatory responses following exertional fatigue", abstract : " there is evidence to suggest that changes in central thermoregulatory control or peripheral sympathetic responsiveness to cold lead to thermoregulatory fatigue and increased susceptibility to hypothermia."

    "Effects of 29-h total sleep deprivation on local cold tolerance in humans", abstract: "We concluded that TSD induced thermal and vascular changes in the hand which impair the local cold tolerance, suggesting that TSD increases the risk of local cold injuries."

    "Cold tolerance and metabolic heat production in male C57BL/6J mice at different times of day".

    "Thermoregulation during cold exposure after several days of exhaustive exercise": "These findings suggest that susceptibility to hypothermia is increased by exertional fatigue".

    Full "Human Physiological Responses to Cold Exposure". I must read that one myself, looks interesting generally.

    "Sleep Deprivation Affects Thermal Pain Thresholds but Not Somatosensory Thresholds in Healthy Volunteers". "CONCLUSIONS: The present findings suggest that sleep deprivation produces hyperalgesic changes that cannot be explained by nonspecific alterations in somatosensory functions."

    It think it's pretty conclusive. The most popular long running article I wrote on my blog was "what temperature is too cold to swim in", because people keep searching with that phrase,and I put sleep loss right up near the top of the list.

    General stress is also a factor, because thermal adaptation (cold hardening specifically) has been shown to be accompanied by a reduction in stress hormones (Makinen, Extreme Cold Adaptation in Humans, (I did a series on it) and if the stress hormones are higher than normal, then there must a corresponding reduction in cold hardening.

  • ChickenOSeaChickenOSea Charter Member
    Oh wow! That's low! My iron's good....I'm hoping this is just a temporary result of stress and fatigue. The water's mid 50's here at the moment. I could always do a mile in that, have a bit of a shiver and feel like a million bucks. It's the different, kind of "yukky" feeling I'm getting lately after shorter swims that's got me wanting to find answers..
  • bobswimsbobswims Santa Barbara CACharter Member
    For me cold water tolerance is most affected by the lack of sleep.
  • JonMLJonML Member
    edited November 2012

    Spent 4+ hours on Sunday morning in Ontario Canada running a marathon. 38 degrees at the start, 40 at the finish. I may have won the prize for least dressed runner. Note the smarter bears in the background in their coats and hats. My wife thinks I'm nuts, but she thought that already.

    Other than swimming, what do you do for cold acclimatization?

  • jcmalickjcmalick Wilmington, DEMember
    Keep the windows open in my bedroom overnight and turning off the heater in the house. Additionally, blasting the AC in the car and having the windows down in the dead of winter helps too! There is no substitute for cold water immersion however and being able to acclimate with time and distance is the key ingredient if feasible!
  • nvr2latenvr2late Central VirginiaCharter Member
    Cold showers, cold baths, and generally underdressing for the weather - older ladies stop me at the grocery store and tell me that I need to wear more than a tank top and shorts this time of year! I also embrace the advice of the CSA that training in water less that 55 degrees is unnecessary and not advised. Our lake and river is currently low 50's - and I will just do short swims at that temp.
  • bobswimsbobswims Santa Barbara CACharter Member
    When I have questions about cold adaption I go to this article:

    Acclimatization to Cold in Humans - National Aeronautics and
    Space Administration
  • loneswimmerloneswimmer IrelandCharter Member
    As swimmers who are forced to swim in less than 55F, since it's below that most of the year, most Irish Channel swimmers think that CSA advice is wrong. Swimming in cold is very valuable for confidence in the channel. It's about 50f now and I'm still doing an hour.

    Thanks for the link Bob. I have a meta-analysis that is very valuable but they took the original link on the Finnish Arctic Institute down.

  • mauprietomauprieto New Orleans, LAMember
    edited February 2015
    In my attempt to acclimatize to cold water, I am trying to approach this in a systematic way (a flaw of mine). When I train for a distance swim, the key metric in my training objectives is distance (km). But when my intention is to acclimatize to cold water, I am facing a dilemma. How does a a 45 minute swim in 15C water compare to a 1 hour swim in 17C water? Which one gets me closer to my goal of swimming 2 hours in 15C water? For this purpose, I came up with a ratio (CWITR...short for Cold Water Index Training Ratio) which is simply: #minutes divided by Water temp. So, in my earlier example, the CWIT Ratio of a 45 minute swim @ 15C is 3 and the CWIT Ratio of a 1 hour swim @ 17C is 3.5. This would indicate that the latter swim would be a more intense cold water training than the former and would be a better training for my 2 hour @ 15C goal (CWITR = 8).

    Does this ratio make any sense to you cold water swimmers? What tweaks would you recommend to the formula (# minutes / Water Temperature) to make it more accurate to the realities of cold water training and cold water acclimatization?

    Thanks a lot for your help.
  • The ratio feels right but it'd be good to get a little science behind it. First off, you need to establish that there's an inverse relationship between water temp and difficulty. This may be tough as a 1 mile swim at 0C, while very hard, is not infinitely difficult. Second, what are the dependent variables at play here? Are these swims with sun overhead, on outcast days, or at night? What current are you swimming with/against? What's the salinity of the water? All of these come into play. I think the idea is great, it just needs to be fleshed out a little.
  • IronMikeIronMike Northern VirginiaCharter Member
    Waiting for the official MSF scientist @evmo to chime in...

    We're all just carbon, water, starlight, oxygen and dreams

  • Leonard_JansenLeonard_Jansen Charter Member
    edited September 2013
    My $0.02 - I would do it is follows:
    1) Construct a scale of difficulty (y axis) vs water temp (x axis). It might be 1-100 (y axis) or more likely a modified log function. The lowest water temp you can stand = max y, min y= temp you are most comfortable swimming at, the highest water temp you can stand (like 98.6 degrees F) =max y
    2) The "difficulty product" of a swim is then distance (or minutes) * difficulty (from #1 above)

    This follows Eric Bannister's theory of TRIMPS (TRaining IMPulSe) in running where a run's difficulty is distance * perceived effort. He used a 1-10 scale for perceived effort. Note that both Bannister's TRIMPS and what I proposed is individualized. If you wanted a "universal" scale of difficulty, maybe set max y at 32 degrees F and 98.6 F and min y to something like 70 degrees F. (Open to debate.) The shape of the line through the points would also be open to debate, but it's definately non-linear.


    “Moderation is a fatal thing. Nothing succeeds like excess.” - Oscar Wilde

  • LeadhyenaLeadhyena Member
    edited September 2013
    Leonard: After doing some research on my own, I'm entertaining the idea that water temperature difficulty could actually be linear w/r/t water temperature minus a constant, assuming equal salinity (which affects thermal conductivity) and training.

    Essentially, we are measuring the effects of thermal conduction on the effort needed to complete a swim. The more thermal conductance, the harder the body has to work in order to replace the thermal energy to maintain a core temperature of 37C. First off, the amount of power the body normally exerts to replace heat lost can be measured by black-body radiation is about 100W (around 9MJ or 2000kCal a day), but variables such as the amount of convection can make that number vary wildly. When people shiver, they use a lot more energy to maintain core temp; that number has been measured as high as 40-50% of maximum exertion.

    However, assuming equal training and body shape, the amount of heat transfer should be equivalent to the amount of effort the body needs to exert to generate the thermal energy lost. Fourier's law seems to describe this situation (assuming no movement) and states that the amount of heat transfer is roughly proportional to the surface area of the conducting surface and the temperature gradient in Kelvin. Newton's law of cooling is the discrete analog of this ('s_law_of_cooling#Newton.27s_law_of_cooling) and states that the amount of energy lost is proportional to the difference in temperature.

    There are some HUGE assumptions here, such as that the water isn't moving, the water doesn't change its thermal conductivity significantly when it gets colder/warmer, the human body doesn't shift to a shivering state during the swim (in this case, dip), AND we aren't trying to cool the body instead of warm it (in cases of swimming in 31C water). But, it can be used as a first case approximation. I would conjecture that instead of using straight up temperature in C, we should use an absolute difference in temperature from a steady point. Human skin temperature is 33C, and makes for a good starting point.

    TL;DR... maybe your formula for effort in the water should be (minutes swam)*(33C-water temp). This seems to fit nicely by dimensional analysis to an amount of effort exerted by rewarming your body (minus shivering) and adds credence to one of @david_barra 's adage about how his pace per mile gets slower by a constant amount every drop of 1C (did I get that right?). In your case, 45 minutes at 15C would be 810 units of exertion vs the same amount of time at 17C would be 720 units.
  • evmoevmo SydneyAdmin
    Two thoughts:

    - Air temp will have to be a factor in any cold water swimming metric. Not as important a factor as water temp, obviously, but still a factor.

    - Try quantifying how cold you feel after each swim as a dependent variable, along with water temp, air temp, & time-in-water as independent variables. For example, when you swim in Aquatic Park you can record how long it takes you to re-warm in the sauna.
  • @evmo: I REALLY like the idea of basing acclimation on how long it takes you to warm up afterwards.
  • timsroottimsroot Spring, TXCharter Member
    Leadhyena wrote:
    After doing some research on my own, I'm entertaining the idea that water temperature difficulty could actually be linear w/r/t water temperature minus a constant, assuming equal salinity (which affects thermal conductivity) and training.

    This assumption seems troubling to me. At the very least, it's a quadratic, I think. @evmo has posted other places that his pace is pretty constant between 68F and 82F (if I remember the numbers correctly), but outside of that range, on either side, his pace slows. Unless you are assuming that you are operating close enough to one end of the curve, I think your trend line will give you some pretty misleading results.

  • Look, if your goal is a two hour swim in 15 degrees, I can assure you of one thing. It will be easier to just go and do it rather than try to understand the maths. Or put it another way, I can spend the next two hours studying this thread, or I can put my speedos on and go for a two hour swim.

    But seriously though, once you have swam a few 7 degree miles, you will find doing one your first 6 degree mile no more difficult than the first 7 degree mile. Then after a few 6 degree miles, you will find your first 5 degree mile no more difficult than your first 6.

    Indeed, my first official Ice Mile3.5 degrees, mile seemed comparitively easy after the many training ice miles previously swam. Acclimatising makes colder temps easy, but you would expect colder temps to be tougher. It's a paradox that will mess with your head.

    So concentrate on swimming not maths.
  • loneswimmerloneswimmer IrelandCharter Member
    @Mauprieto, I asked myself a similar question some years. Like you, the largely rational side of my mind wanted to be able to quantify all the factors leading to heat loss. I kept asking myself why there was such variability in people's cold tolerance, where there wasn't an apparent great physical difference. It lead to me writing the first long series on my blog, on cold adaptation in swimmers. I read a lot of papers, where I could find them, I even tried using Wolfram Alpha to get answers to certain questions like trying to treat the human body as a black box.

    As @leadhyena says, the variables are significant, wind speed and air temperature are huge factors and some are internal and can't easily be measured. The externals alone are long, (add wind direction and speed, air humidity, water surface state). The physiological variables include weight, size, body fat, stroke rate, heart rate, presence of stress hormones, possible low level undetected infection, sleep, recent food intake & glycogen levels. The stress hormone and heart rate items are something that are a good measurement of experience. Early in cold adaptation both will high, even precipitating elevated respiration and noticeable cardiac palpitations whereas even though you know it will uncomfortable or even painful once you've done it enough times, you are still completeley calm.

    I eventually gave up the idea (for myself anyway). In fact, and I'm not telling you to do this, but letting go of trying to quantify cold ability so rigourously I think helped me, maybe because I relaxed a bit more, stopped trying to be the same as other people whom I perceived as better (and I believe one of the best if not the actual best cold water swimmer in the world is a Sandycove swimmer), and because I saw cold as a moving target.

    Because you have more than two variables and most of those you can't adjust (water temp and air temp are the closest to adjustable from a practical viewpoint) there's no way I think to come up with an independent scale. If you've seen a Four-Corner experiment with less variables, but which can be quantified,let's say four, as I recall the maths get complicated to assess the best outcomes (rather than where you have two variables and you simply adjust until you get the best result), and even if we could adjust, it would be even more complex. This is irrelevant since we can't even measure many of variables practically.

    What you could do, and I did it for myself about five or six years ago, is to create a diary of how long you can swim at each full or half degree drop, what you feel like mentally at each temperature drop and your recovery time. You also want to record initial shock effects (e.g. I won't get sinus pain until under 7C).

    It then becomes like the medical scale for assessing pain (almost literally) and easier to measure progression season on season. It had three primary benefits:
    1. I could establish an initial personal baseline.
    2. I could subsequently gauge personal improvement.
    3. It does allow you a scale to allow discussion with others.
    It's not a short term project, but doing now going into autumn is a good time to start.

    Another thought is having an hour swim target. Assuming I do any winter swimming, I know that at 10C water temp and 10c air temp I should be able to swim an hour (I can do more if I specifically stay in longer at lower temperatures but a five minutes variation can be very significant if you are approaching Moderate hypo. (One friend calls it the combined 20). If adding air and water temps equals 20C, this allows him to swim for an hour comfortably .)

  • Loneswimmer forgets that acclimatising will make the lower temps easier. I remember gasping for breath entering at 12 degrees, but now think nothing of getting in at 5. Does that mean 12 was colder than 5? Crumbs, after a season of ice swimming 12 will feel toasty. Bur after a summer of 17, 12 will feel chilly. I can't see how you can calculate anything meaningful. Other than simply recording the dates temps and durations of your swims and how you felt and how you recovered.
  • mauprietomauprieto New Orleans, LAMember
    Haydn wrote:
    Look, if your goal is a two hour swim in 15 degrees, I can assure you of one thing. It will be easier to just go and do it rather than try to understand the maths. Or put it another way, I can spend the next two hours studying this thread, or I can put my speedos on and go for a two hour swim.

    I hear you, and I started my question saying that I have the flaw of trying to approach things in a systematic way. The fact is that I am curious into how things work, and was intrigued in finding out from the cold swimmer gurus out there if my rule of thumb (minutes/temperature) is a somewhat adequate metric for the relative difficulty of a cold water swim. Concentrating on maths helps my swimming. I end up putting my speedos more often if I set myself specific objectives. I find value in understanding how 60 minutes @ 15C compares with 70 minutes @ 15.5C water.

    I will gladly sacrifice a day's swim in exchange for the insights gained from @Loneswimmer, @evmo, @Leadhyena, @IronMike, @Leonard_Jansen, @timsroot, and @Haydn. Nothing wrong with learning something new now and then, so definitely time well spent for me. MSF allows me to learn from the best out there and get input from different perspectives in order to draw the right conclusions for me, and this thread is a great example. Thanks you all for the time dedicated to shed light into my question.
  • loneswimmerloneswimmer IrelandCharter Member
    edited September 2013
    @Haydn, I didn't forget acclimatisation. I was trying to give @Mauprieto something that might him, that helped me early on, coming from a similar mindset.
    It's why I said that a personal log demonstrates a changing and improving ability, i.e. acclimatisation.

    Plus I like writing about cold.

  • malinakamalinaka Seattle, WACharter Member
    I like @loneswimmer's advice on not trying to quantify it. Four months ago, I was trying to come up with a metric to plot for each swim, thinking each day should be a point on the path towards acclimatisation. However, like @loneswimmer I gave up on this, seeing the challenge of distilling a hundred variables into a single datapoint as a poor use of my time, time which could otherwise be spent seeking out cold water and swimming in it.

    This isn't to say that one shouldn't record and asses acclimatisation qualitatively, collect some info on time, water temp, how you felt, Shivering Index, Forearm Cramping Index, core temp, and maybe Glasgow Coma Scale (if it's a bad day), and backcalculate something useful for next time.

    I don't wear a wetsuit; it gives the ocean a sporting chance.

  • JenAJenA Charter Member

    From (, I believe this data is based more on survival stories than marathon swim performance. Still, it provides a clean benchmark as to where you are in the slow cooler/fast cooler continuum.

    Grip strength would be another good metric. I've participated in hypothermia research, and that's one of the metrics they used. There's also the Cold pressor test, but I think many of us would ... blow that out of the water? Hehe. :-)
  • bruckbruck San FranciscoMember

    An interesting new study by Tara Diversi and colleagues in Extreme Physiology & Medicine.

    Core temperature rate of decline was slower in the first 3 h compared to the last 3 h of the swim. Older age was significantly correlated to TC change and SR change. Absolute and percentage body fat (BF) were not significantly associated with higher TC. Mean SR over the 6-h swim was 57.8 spm (range 48–73 spm), and a significant decline in SR was observed over the 6 h. A strong, positive correlation was found between SR change between 3 and 6 h and TC over the 6 h and TC from 3–6 h.

  • JenAJenA Charter Member

    That's a great article, @bruck! Too bad about the small sample size of 9, but really good to see the analysis.

  • SpacemanspiffSpacemanspiff Dallas, TexasSenior Member

    Interesting there was no correlation between bioprene and core temperature change--second largest drop in core temp came from swimmer with the highest body fat (43%). Is it a myth, then? Or just too small a sample size?


    "Lights go out and I can't be saved
    Tides that I tried to swim against
    Have brought be down upon my knees
    Oh I beg, I beg and plead..."

  • ColmBreathnachColmBreathnach Charter Member

    was there a measure of relative effort of swimmers, ie swimming hard or easy, as this would also contribute to temperature drop?

  • JSwimJSwim western Maryland, USSenior Member

    They used stroke rate (SR), and SR changes, as a gauge of effort level:

    In freestyle swimming, increased SR is associated with increased metabolic heat production and typically results in an increased velocity [47]. Stroke rate is also related to energy output, and thus a decline in SR is generally indicative of a swimmer’s state of fatigue and performance [48].

    Life begins at the end of your comfort zone. --Neale Donald Walsch

  • Hi All,

    This was one of our small studies, and it's very difficult to make conclusions based on these 9 swimmers. We did a study with 21 swimmers over an 8 hour swim, but had a malfunction, so we only have relative rate of decline and not absolute numbers. So the likelihood is that this data won't be published. This gives us something to think about though. Anecdotally, from observing these two studies, it is obvious that cold tolerance and thermoregulation are not always the same. We didn't have a measure to test it, but body fat seemed to allow people to tolerate the cold, whilst not always protecting them from core temperature decline. Also, FYI, for analysis when we took out the outlier with high BF%, the results still showed no correlation to body fat %. I'm behind on my analysis, but we hope to have some at least another paper out this year. Personally, if I were looking at this research to see how it could help me, I wouldn't start losing weight and thinking I could tolerate cold water swims. We know lean people can do cold water swims, but there are other contributing factors such as muscle mass, speed, nutritional intake and exposure to cold water that need to be accounted for that are not explored in this research.

    Happy Swimming


  • Anectdotally , we have have had uh, rather LARGE people who are not acclimated still get hypothermia so BF% is not always an indicator.

  • Using A&D (10% lanolin) or expensive 90% lanolin helps me.

  • tortugatortuga Senior Member

    Thanks for sharing this very interesting study.

  • andissandiss Senior Member

    Interesting- great post!

  • phodgeszohophodgeszoho UKSenior Member

    "Acclimatization or acclimatisation (also called acclimation or acclimatation) is the process in which an individual organism adjusts to a change in its environment (such as a change in altitude, temperature, humidity, photoperiod, or pH), allowing it to maintain performance across a range of environmental conditions."

    I have my views on the subject but very curious to hear what other people's are.

    When people talk about marathon swim training for cold water acclimitisation are they generally talking about adapting mentally for the cold challenge or do people believe their body is going through physical changes that over time make them better able to endure lower temperatures?

    Just to clarify I am not talking about things like deliberately gaining weight, I am talking about the simple concept of gradually exposing yourself to longer colder conditions as part of training. Swimming, Ice Baths, Long cold walks, cold showers, shopping in Waitrose etc.

    What do people believe?

  • JSwimJSwim western Maryland, USSenior Member

    I absolutely believe (and have seen it in myself) that there are physical adaptations to repeated cold exposure.

    The mental aspects are important too, as they are in most any stressful situation. But a good attitude towards cold does not make up for lack of physical preparation. Though the reverse can be true. (As I found out for myself ice swimming in Vermont this February.)

    My 2 cents! I'm curious what others opinions are.


    Life begins at the end of your comfort zone. --Neale Donald Walsch

  • phodgeszohophodgeszoho UKSenior Member

    @JSwim "I absolutely believe (and have seen it in myself) that there are physical adaptations to repeated cold exposure."

    Can you elaborate and give some examples? Thanks.

  • evmoevmo SydneyAdmin
    edited April 2018

    I believe it is difficult to distinguish physical and psychological adaptations!

    Other cold water-related threads here:

  • gregocgregoc Charter Member

    To add to Evan's comment, you can't separate the mental acclimation from the physiological acclimation. One affects the other. You definitely mentally acclimate to cold water. You get use to the feel and your mind begins to tolerate colder water. This in turn effects your physiology. When talking physical acclimation, there are a lot of factors the can change from day to day (how much sleep you have had, your diet, your "mood", even your gut biome).
    So the short answer is both. You both mentally and physically get accustomed to colder water. That said, you can never prevent hypothermia from eventually creeping in.

  • SpacemanspiffSpacemanspiff Dallas, TexasSenior Member
    edited April 2018

    loneswimmer has authored and aggregated a ton of cold-water information on his blog. He discusses the difference between psychological vs. physical adaptation and between "habituation" and "acclimatization". Habituation, he describes, is more about repeated exposure, even brief exposure, leading to a reduction in the "shock" related symptoms (rapid breathing/heart rate and muscle contraction) whereas acclimatization is more about physical adaptation from prolonged exposure (increase in subcutaneous/"brown" fat, very different from building up fat from weight gain).

    For what it is worth, I find that I can make tremendous strides in habituation in a very short period of time. I can go from barely making it 1 minute in a cold shower to very relaxed 10 minute cold showers in about a week. This translates into submersion for me more directly that what I have heard from others. I don't heat my pool so during the early spring, its 50-60 degrees. So when I'm ready to start habituating early in the swim season, after a few days of cold showers, I start/end each day with a dip in the pool. Within a week, I can watch television fairly comfortably in the water for 20-30 minutes.


    "Lights go out and I can't be saved
    Tides that I tried to swim against
    Have brought be down upon my knees
    Oh I beg, I beg and plead..."

  • I believe in physical adaptation. When I first started swimming in cold water (hovering around 50 deg F), I had a very strong physical reaction where my chest felt constricted and it was hard to catch my breath. I could only stand it for a few minutes and scampered quickly for the shore. Over months of regular exposure (at least 1x/week), and for gradually longer swims, that feeling has gradually dissipated and I don't have any reaction. I'm conscious that the water is cold, for sure, but it feels "normal" now and never shocking. My breath and heart rate stay calm and controlled. Reading comment above though, I'm certain mental adaptation is connected, but to me the physical feeling is what's front and center. And oh... the endorphin rush that keeps me coming back again and again.

  • SoloSolo B.C. CanadaSenior Member

    For me the hardest part was mental. Go get in the water was harder than the swim. That being said, I have noticed many adaptations over the last 2 years of winter swimming. I generally take a minimum of 10 minutes to get into the water and get submerged. When I was first starting out, the brain freeze would last up to half an hour, now it goes away quickly and seems like an inconvenience, and not a painful experience. Also, the colder the water, and longer the swim, the less mobility I would have: my hands and wrists would claw, elbow and knee tendons retract, and feet refuse to straighten. With more exposure, I can now swim longer and colder with less immobilization. Early on, the shock of cold water on my head would cause me to hyperventilate for up to 20 minutes, resulting in a very uncomfortable feeling while trying to swim.
    When I began swimming, I was afraid of cold water. Terrified, and for no real reason as I had never been in cold water before. Now as I contemplate a swim, or approach the water, I know what is going to happen, how it is going to feel, and what my reactions are going to be. The fear is gone completely now, and I feel better for having conquered it. Acclimating for a long cold swim took 2 years for me, and now I am comfortable and happy at lower temps.

  • SamSam Member

    Solo said:
    When I was first starting out, the brain freeze would last up to half an hour

    I'm glad you raised the brain freeze issue. My training lake opens in a couple of weeks time when it finally hits 54. I have only done pool swimming over the winter so my first dip is always a painful experience...but its the headaches that get me the most. I tend to find that my second swim (which is usually a week later) is so much better at almost an exponential level (i.e. I may last 20 minutes in my first swim but 40 - 60 minutes in my second swim)

  • JSwimJSwim western Maryland, USSenior Member
    edited April 2018

    phodgeszoho said: Can you elaborate and give some examples? Thanks.


    @phodgeszoho Until 2 years ago I was an average pool swimmer and middle aged women, with regards to what I thought were comfortable temperatures. (And I've lost maybe 10 lbs, so it's not extra insulation.)

    Then I purposefully cool water adapted using Cool Fat Burner vests (both styles) and cold showers, so I could swim in the Chesapeake Bay in May (water 60+/- F, air 45 – 55 F, cloudy, rainy). It worked, and I was hooked. I loved feeling the cold on my skin but warm in my core. And I swim faster too, down into the 60s F.

    But now I am teased (in good fun) at the pool for disliking the “good” temperatures (above 82 F) and “how can I love it so cold” (below 80 F). And at home in the winter, when my husband sleeps with 2 blankets and a heavy comforter, I'm happy with a light blanket. And I used to be the cold one.

    Mentally, I didn't have a problem with “cool” water (55 F +). I naively thought that if others could do it I could too, once I trained. (There is discomfort initially, but it's manageable.) Ice swimming (short stuff, 50m, 100m, 200m not an ice mile)? Not the same for me. I trained for it, so physically I was as good as to be expected. I had no trouble breathing, no headache, "normal" numbness. But it was so very hard mentally. But I plan to do it again. The community is awesome (lots of Marathon Swimmers, how could it not?) and the experience was very excellent mental training.

    Life begins at the end of your comfort zone. --Neale Donald Walsch

  • curlycurly Issaquah, WASenior Member

    Solo said:
    ...Now as I contemplate a swim, or approach the water, I know what is going to happen, how it is going to feel, and what my reactions are going to be...

    To me, this seems like most of the battle. The anticipation, the dread etc. Once you've taken the plunge enough, it's not such a big deal. I used to have that feeling on the starting blocks. Now I'm working on not letting that thermometer scare me. (I'm so tempted to say something about it being a matter of degrees, but I'm not going to.)

  • ToadToad Member

    I found that the water entry is the worst part. I started back into the OW about 1.5 months ago. Water temp was 52 the first weekend and I was able to knock out a good hour long swim. The shock made it hard to breathe at first but I got over it quickly, I discovered I really enjoyed the challenge of the cold water and maybe even enjoy the strange looks from all the wet-suit wearing swimmers every week.

    I guess my take is that there is more mental adaptation than physical (for me).

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