How to Conduct a Personal Experiment: Cold Water Plunges

I’ve always been a self-experimenter, even when I didn’t realize it. Back when I raced competitively, I logged – compulsively – all my training routes, times, and distances. My logging didn’t begin as a grand self-experiment. It was just a way to authenticate my hard work. See, races were their own reward. Beating the other guys? Nothing sweeter. But those were few and far between. To get to those races, I had to train, day in and day out, with nothing tangible to show for it save for sore joints and a bottomless pit for a stomach. Filling those blank spaces with numbers made what I’d done somehow tangible, and the agony of training day in, day out became more bearable.

Of course, patterns emerged in those logs. I’d notice a string of particularly strong training days and think to myself, “What was different that week?” Had I eaten a particular something? Had I not eaten a particular something? If a weak sequence appeared, I’d wonder the same thing and explore my past. “Oh yeah, that was the week I had friends in town and I stayed up late every night” – maybe sleep does matter! Or, “I trained fewer days that week and my times actually improved” – could less possibly be more? And so from the practical, the numbers, the data, the objectivity, I gleaned the intuition, the insight, the lessons to be learned.

Now that I’ve internalized all those training lessons learned from my accidental self-experimentation, I don’t have to log it. I just do it. Same goes for eating. I don’t calorie or carb or protein count; I just eat. You can get there, too, and I suspect many of you have with regards to certain aspects of your diet or your training. But before you get there, before you’re dialed in, you have to experiment. You have to start with an idea, give it an honest shot, and see it through to the end. Though making your experiment air-tight enough to pass peer review isn’t necessary, try to be as systematic and scientific as you can. It will pay off and your results will have that much more meaning.

I hear people getting up to leave. I know, I know. We’re all about the ease of Primal eating, exercising, and listening to one’s body while looking at calorie-counting with suspicion and often barely veiled scorn – “just follow these basic rules and everything will fall into place like so” –  but logging data, analyzing data, and drawing conclusions from said data is really about honing your intuition. It’d be nice if we all maintained that Primal connection to our bodies, but most of us have not. Most of us have lived lives divorced from our bodies, eating weird pseudo-foods, strapped several inches of rubber to our feet, sitting in the same place for ten hours a day, staring at one electronic screen or another instead of the wide world around us, sleeping in rooms with bright blue green blinking shards of light filling our dreams, and we’re all a little confused. That’s okay. That’s to be expected. We can come back from this to reclaim our intuition, and data logs, journals, and self-experiments are how we get there.

You know how people say you go to college to learn how to learn? This is kinda like that.

What’s cool is that we can all learn something from a self-experiment. No matter what you know or think you know, you have a weak spot that can be identified and hammered out by systematically logging, journaling and testing. I know this because I have plenty of them myself. Ever since I wrote that first post on self-experimentation, I’ve been playing around with my own experiments, and I have an effective, simple methodology for testing. Also since that blog post I’ve quietly been putting the finishing touches on a new book, a 90-Day Primal Journal that will contain this methodology and deals with precisely this subject. It drops later this month.

Thus, this post marks the start of a new self-experimentation series on MDA. In the coming weeks, I’ll introduce new concepts to try, parameters to track, and experiments to run, but today, we’re going to cover cold water plunges.

Why cold plunges? A few reasons. First, cold water immersion is sort of a hot topic these days around the Primal and ancestral health community. It’s on people’s minds, so they’re already primed to consider it. If I had just come out of the blue with a random charge – “try plunging your mostly-naked body into cold water!” – you might write me off. This way, it’s not such a foreign concept.

Second, the weather’s warming up (at least for those of us living where summer is approaching). You’re more likely to try something as physically unappealing and discomforting as a cold plunge when it’s warm out. When it’s cold out? Not so much. For many people, the winter months are traditionally associated with hot mugs of coffee, hearty soups, and raging fireplaces, not feed troughs full of hose water doubling as immersion baths. This is a good time to ease into the practice of plunges. And who knows – maybe you’ll dig ’em so much that you consider employing them in winter, too.

Third, for all the negative (and positive) stuff surrounding cold plunges, I think there’s real merit in them. They aren’t faddish, they aren’t (necessarily) dangerous, and though they’re not magical, brief exposure to cold can serve as a potent hormetic stressor that can induce positive adaptations.

Fourth, I’ve been incorporating them into my own routine for a few years now, and I’ve noticed a big difference. I think you guys will, too, and I think a community-wide push to systematically test the effect of cold plunges will give us a lot of data.

Okay, so how do I do it?

Come up with a goal that cold plunges may help realize. The link between your goal and the plunges should be plausible, of course. People make a lot of fantastical claims about the benefits of cold water plunges. Some say it’ll make you immune to the ravages of even the most pernicious pathogens. Some folks claim that cold water plunges will fine tune your metabolism. And some people swear that there’s no better hangover cure than a few minutes in some really cold water. While I have little doubt that there are kernels of truth hidden within most of these claims, the bulk of the established research has hitherto focused on workout recovery and fat loss.

Here are a couple ideas, but you can definitely come up with your own:

  • I want to improve workout recovery.
  • I want to lose body fat.

Then, come up with a hypothesis:

  • Post-workout cold plunges will improve recovery, reduce soreness, and increase subsequent performance.
  • Daily cold plunges will reduce body fat without affecting lean mass.

Let’s choose “workout recovery.” Identify the variables and note how they may affect the outcome:

  • Water temperature – Is colder better? Is there such a thing as “too cold”?
  • Time spent plunging – Is five minutes better than three? Is there such a thing as “too long”?
  • Frequency – Every day or every other day?
  • Contrast – Is cold/hot contrast water immersion better?
  • Body parts immersed – Is full body necessary? What if I just stick the legs in? Do I need to dunk my head? Do I only need to dunk the body parts I just worked out?
  • Time of day – Does it matter how far post-workout I take the plunge?
  • Workout intensity and volume – The intensity and volume of the workout itself are obviously huge determinants of how well you recover.

Test one variable at a time. If you change more than one variable from one plunge to the next you won’t be able to attribute the positive or negative results to the accurate variable.

Then, decide what you’ll be measuring in order to quantify “workout recovery”:

  • Subjective perception of soreness, ranked 1-10.
  • Heart rate upon waking, indicative of “recovery.” Overtrained individuals will often wake with elevated heart rates.
  • Weight lifted, reps hit, sprint times, mile times, and other markers of performance.

Oh, and if you want really strong results, be sure to introduce a period where you remove the cold plunges and note the change (or lack thereof) in workout recovery.

There are inherent limits to this brand of personal science, but so what?

Again, you are not a team of objective scientists, slavishly eliminating confounding variables (or trying your best) to test a single, solitary change and get published. You’re the scientist, the subject, and the reviewer. Ultimately, you’re just trying to help yourself and improve your health, not get published. You can cut corners. You won’t be able to eliminate confounders. Your diet won’t be completely static throughout, nor will your workouts, or the weather, or your sleep, or your stress levels. Things may have changed without the introduction of the variable, since working out consistently will generally produce improved performance, with or without a cold plunge. These things and more will affect the results of what you test, but that’s okay. After all, that’s life.

Okay. I’ve said my piece. Now, it’s your turn to get out there and get into some cold water. Shoot for around 60 degrees F, which will feel cold but not shockingly so. Stay in for as long as you can handle to start. Be sure to let me know how it goes!

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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88 thoughts on “How to Conduct a Personal Experiment: Cold Water Plunges”

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  1. Cold plunges…I do these weekly while making my way down one of the local mountains which i hike. The mountains have a few streams, each about a foot to one and a half feet deep. I simply sit in up to the waist (wearing a bathing suit). I’ll even take my shirt off and soak my torso. It is so refreshing after a hike. I often hold a metal rod while doing this, too, because i heard that metal conducts minerals into our bodies from natural water sources; not sure if this is true, but what the hell…

  2. Last summer I started using cold showers to recover and it was a big help. This summer I have been employing cold baths for about 10 minutes and about 30 seconds after laying in the tub, I find the cold water to be extremely relaxing. Also, it seems like I can handle cooler water with a bath instead of a shower. I’ve been doing lat pull downs, which I’m not used to, to train for pull-ups. Without the cold water therapy, I think I’d be having a very rough time with the training!

  3. My personal experiments show that 40 degree water is best for muscle recovery. 60 degrees or less seems to be the sweet spot for weight loss. It has been said the cold receptors in the skin begin firing at 50-55 degrees.

  4. This is SO EXCITING!!! I am glad you are starting this series! I am not sure about the cold water plunges, because I don’t want to improve workout recovery or lose body fat and I am not sure what it might help me with….but yeah I have done a lot of self experimentation lately. “If I stop eating dairy, my post nasal drip will go away.” Sucess! “If I eat 2500–3000 calories a day, in addition to working out, I will build more muscle than I have been on less calories.” Yeah my butt and thighs just got fat…but I also got my period at the time so I am still giving this one a go… Anyway, stuff like that. I just never thought about being more rigorous about logging and journaling. Lots of people have recommended it, but I haven’t had the patience I guess. Maybe now is time to start. This is fantastic, it really renews a sense of adventure in someone who has become but bored and perhaps complacent. Onward into uncharted territory!!! Thanks Mark!

    1. Instead of cold plunges, you could simply try rinsing your legs with cold water for 20-60 seconds after a warm shower.

    2. There seems to be some anecdotal evidence that cold plunges or cold showers lead to fewer colds and illnesses, and also better skin. Plus, some people find them energizing. These might be things worth experimenting with.

      1. I remember that hot and cold showers were meant to be good for your immune system.

        This comes at the perfect time, I was gonna start with hot/ cold shower this wekk… no bath, so I hope this will still do me some good. 🙂 Goal is weight loss.

        I am still tracking everything I eat, and am impressed how quickly I now notice trouble makers. Diet coke after 4 weeks of a break? Macadamia nuts for lunch? Severe stomach cramps. The verdict is still out on eggs, will have to try again next week – they were not good for me after 4 weeks of VLCD.

        Okay, so cold showers next…

        1. I track everything I eat, as well. Now, I always know what irked my digestive system or what new habit caused the scale to climb.

          Plus, I just like knowing what I put in my body — it’s the only one I have, after all.

        2. I used to eat eggs several times a week for years. Then, one day i experienced severed cramping and diarrhea after a meal of only eggs. This happened many times afterwards, so much so that i rarely eat eggs now. In short, i developed an allergy to eggs. Apparently the same thing happens to many others too.

          In order to track the effect of certain foods, i think it helps if you consume them on their own.

  5. You missed the most immediate and recognizable benefit of cold water on the body: incredibly good mood and energy afterwards.

    People with depression and anxiety are finding huge benefits from cold water showers because it seems to almost reset your brain and stop circular ruminating type thinking and it leaves you feeling glorious all over and full of energy for hours afterwards.

    The other benefits are just gravy as far as I’m concerned.

    Try a normal shower then set it to full cold and “dance” in and out of it to cover as much of your body as possible and try to soak your head and face as much as possible.

    I guarantee you will feel incredibly positive and energetic if not laughing out loud right after.

    1. Couldn’t agree with you more!

      After a stressfull day/week, most people just want to take a long, hot bath. But end it off or substitute it with a cold shower or plunge and I promise you’ll feel even more relaxed and sprightly

    2. I did this once but instead of laughing, I was crying. Middle of winter in NJ, living in an RV and the pilot light kept going out during the night. Maybe it’s different if it’s a choice (I worked in NYC and couldn’t go another day without a shower).

  6. I just started taking cool/almost cold showers rather than my usual steaming hot ones. I can’t say that I’m at the point that I like it yet, but I have noticed that my tolerance for the cooler water temp does seem to be increasing after less than a week. Maybe by next week I’ll be able to say that I like it…

  7. Richard Nikoley has been doing much investigation into this matter, as well. Then again, I’m sure that you knew that.

  8. As a kid I’ve always slept with my room as cold as it could get(I live in Ohio so winters get rather cold), and still do however being based in California doesn’t make for a very cold night(even in winter). As a kid and even now I rarely get sick. I started doing “cold therapy” as I call it, and drive to work with the windows down in the morning, take a cold shower after my workout in the afternoon, and a cold shower at night before I go to bed. I have notice a significant reduction in the soreness level overall which is really encouraging. I hope also that the “fat burning” works also, because this would be so simple for ANYONE to lose weight and become healthier overall.

  9. Ok, can’t do the cold plunges, sorry, but I have been logging everything from activity to weather for the last five years and it is very interesting. I can go back and actually see what happened but more importantly, why. I haven’t reached the stage where I can quit logging activity yet, but soon I should be at my goal and have all that knowledge of why things change or happen so I am better prepared as I move forward.

  10. Lake Michigan is pretty damned sweet this time of year on a hot day…Cold is more than hormetic stressor, I think…it reduces inflammation and the inflammatory cascade, relives pain, and give a person a psychological boost, for sure. I really have started to love them, after a long period of loathing them…funny how that works…

  11. Started these a couple of months ago when Nikoley did his first write-up on it. Cold tap which was around 52-58 degrees F in a large jacuzzi tub. First few times, could only do less than 20 minutes, but have since logged a few 35+ min sessions.

    I’m a fairly lean guy, so no noticeable reductions in body fat, but I certainly notice improved recovery. However, some of this is from better eating, so who knows how much is attributable to each.

  12. I start with a warm shower and then turn the hot water off to finish up. It helps start the day off better. I’ve noticed my warm shower is no longer steaming hot because I no longer like the water being that hot. Haven’t convinced anyone else to do it yet though. Same goes for the diet.

  13. Great timing! I recently started cold showers in the morning, with “Tim Ferriss” style cold baths at night. My primary goal is to burn off the few lbs I gained last semester, and then I’m shooting for even lower body fat.
    In the week I’ve been doing these, I’ve dropped about 5 lbs, and my moobs (a remnant from my obese days) seem to be shrinking daily. I’m logging and will be excited to share my results.

  14. We swim in the Great Lakes year round and only wear wetsuits when the water is below 45F. These aren’t in-and-out “polar bear” plunges, but 30-40 minute immersions. I can vouch first hand about the physiological benefits of this extended cold water exposure. In addition to what you cited above, there are extended mood benefits due to anti-depressive effects of cold water exposure. All good stuff!

  15. I have actually begun taking cold/cool showers before bed to help fall asleep. It has worked pretty well.

  16. After a hot shower, I let cool – not cold – water run on my arms and torso, both front and back. This is a classic hydrotherapy treatment to increase circulation and detoxification and decrease inflammation. It’s the change in temperature that is important, but it doesn’t have to be ice cold to work.

  17. My mom used to rub ice on her face and neck for 10-15 mins every night. I never asked he until recently and she said it invigorated her skin and closed her pores. Not sure what that did but she had a beautiful complexion well into her 70’s!

    I usally just say something inappropriate to my wife and she gives me a cold slap in the face! It works.

  18. I have been obsessive about keeping records concerning weight/eating/exercise for years, and love to experiment (on myself and only occasionally others … ) I go back often over the data to find the links. The major overall factor when I felt the best (and felt I looked the best), as confirmed by my blood work, is not one I can replicate unfortunately so looking for everything else I can do.

    I am cold all the time, due to the fantastic job I’ve done messing up my metabolism, but maybe some hair of the dog might be the ticket to restart my fat burning, eh? I am not sure how to quantify fat loss easily, I guess I’ll use overall weight. I will start with a bathtub of cold water tonight.

    1. I used to get so cold after showering. When I let the tap run cold for the last few minutes of my shower, I felt warm afterwards, and stayed warm.

  19. I started taking cold showers last year training for a Tough Mudder. I found that my recovery after working out was quicker if I took the cold showers. Sometimes after having a hard trail run I will immerse myself into the cold waters of the James where I run it is very helpful to my knees and feet. I continue to take cold showers after working out and after a hard day at work.

  20. Great post!

    I have studied with some Systema (Russian Martial Arts) folks, and they are big advocates of short cold water dousing/plunges. One bit of ‘research’ I’ve done is that I’ve noticed over the years whenever I’m close to getting a cold, if I douse several times daily it is enough to drive off the sickness before it really sets into the body. It’s far more effective than any herbal supplement or standard medicine I’ve come across.
    It’s more of a quick shock treatment, and I get a big heart rush immediately after each dousing. Seems like there are many different ways to use cold water for health, this being just one of them….

    1. Oops – I meant ‘heat rush’ not ‘heart rush’ – feels like a quick, instant ‘fever’ for a few seconds….

    2. I’m with you 120% I have studied Russian Martial Arts since app. 2005. I have not had a cold in 7 years. If I think I might be getting a cold, I get my 5 gal bucket of ice water and slowly pour over my head.
      Sometimes twice a day the heat rush kills it every time. A cure for the common cold.

  21. But cold showers give me goosebumps which make my leg hairs grow which is not pretty at CrossFit 🙁

  22. Jack Kruse is the master on this subject- he is walking talking proof on cold thermogenesis. I just started cold soaks in the tub and shower in cold water. My husband says it has improved his skin and lowered our gas bill.

  23. My favorite part after a few hours in hot water and steam at the Kabuki hot springs in SF was the total immersion in the cold plunge. I could hear my hair sizzle. I felt like I’d been in a meat tenderizer. I’m inspired by the memory and all the talk, it’s cold bath tonight!

  24. Think I’ll give the cold showers a go. The lakes in Arizona near me are not cold unless you go deep. At home, I don’t want to use as much water as is needed for a bath (the conservationist in me). Showers it shall be!

  25. As much as I respect and admire your blog and your approach, Mark, I can’t do what you’re suggesting here. This “using yourself as an experiment” is just too obsessive and self-absorbed for me at this point. I want to get in tune with my body, not tune it. I think the lust for control over ourselves is a very real problem in our culture. Our attitude towards what we do also affects the outcome; I believe there is a good bit of the placebo effect going on here. How much does wanting something to work actually make it work? And then we attribute that result to what we’ve done, instead of our mental state? It’s impossible to know, isn’t it? I also happen to think our collective love-affair with all things scientific and measurable is a bit much sometimes. So to each his own. Have fun.

    1. Gydle,

      The benefit to self-experimentation is that we are all different. I have found that when I add dairy to my diet, nothing bad happens. However, for my friend, his weight loss stops…

      We are all different, massive statistical studies help steer us to understanding our race — but self-experimentation helps steer us to understanding ourselves.

      The placebo effect, if it is actually affecting you, is powerful. So why not take advantage of it? If positive thinking, or tracking your weight loss, or checking your blood pressure presents a positive result — regardless of the reason why — then it’s a positive result and that’s great!

      Remember statistical significance is not as powerful as self-significance. If something works for you, focus on that.

      1. sorry, I meant understanding our species — Race was not intended

      2. Yeah, I’m sure you’re right. But I just can’t stomach all the tracking and measuring involved. It probably comes from my history of somewhat disordered eating as a teenager, where the control factor got way out of hand. It took decades to recover and I have no desire to revisit that mindset. I think I have an intuitive feel when something is or isn’t working, or at least I like to think so. 🙂

        1. We all “self experiment” on ourselves at some point even when we don’t realise it. 15 beers last night was not a good idea, note to self: don’t do that again. It can be as simple as that or as complex as Mark’s example. We should be thankful to these people who go to the trouble for our benefit. The whole Paleo / Primal lifestyle is not about following 1 person blindly. This lifestyle is not a 1 size fits all. We all do it differently that benefit each of us in different ways and the only way you find this out – is self experiment.

  26. Well I’m really can’t contribute any sophisticated research, but when I first started my job working in a farm shop I went from sitting on my butt all day to literally being on my feet all day, I couldn’t even sit down to eat, and I was carrying heavy veg about for a few hours too. My feet and lower legs were covered in broken capillaries from day one. My feet were so sore after work I couldn’t sleep. My colleague suggested bathe my feet in cold water when I got home but instead I showered them with icy water from the handshower for about 10 minutes after each shift and it really helped! The pain and swelling went away really quickly and after about a week I just didn’t need to do it anymore and the broken capillaries healed. I’m pretty sure this would have happened given enough time, but it really expedited recovery I am sure.

  27. There is a well-known bodily response to closing your eyes and splashing cool or cold water on your face: your heart rate will slow, along perhaps with slowed respiration, and some diversion of circulation to your core. This is a response that may be responsible for saving the lives of many people (and pets) who have fallen into icy water and would have drowned or suffered brain damage from lack of oxygen from their extended submersion; in some cases being revived OK after 20-30 minutes underwater.

    Perhaps the ‘recovery’ enhancements that we’re talking about here are related.

  28. Many moons ago when I was still eating SAD, I worked out regularly for awhile at a gym with a pool and a hot tub. Sometimes after my workout, I’d take a dip in both, sometimes a few times. I noticed a much improved recovery time on those days. I had forgotten about that – thanks for the memories. 🙂

    I’ve also not been recovering well from my workouts now that the weather is much warmer, so I think I need to try this.

  29. I wonder if a cold shower would help like a cold plunge would? My fiance LOVES finishing a hot shower with a blast of cold water.

    Generally it includes spraying the cold water on me without warning. That might be the appeal.

  30. I just tried this out 2 nights ago, and had a twinge of anxiety while immersed. I stayed in for 15 minutes and felt fine. Cold and goosebumpy, but okay. After toweling off and getting into warm clothes, the heavy duty anxiety attacks hit and wouldn’t ease for quite awhile. I was so hoping for good results, but maybe my body just doesn’t like this cold water therapy.

    A few months ago I tried another type of cold therapy – running around on the outside deck in shorts and a tank top in 28° weather for 30 minutes. Same thing happened afterwards – major anxiety attacks. Blah. 🙁

  31. I cannot tell you how psyched I am as a science teacher that you are endorsing The Scientific Method as a life strategy. I’m totally sharing with my classes tomorrow, thank you!

  32. Comments are so essential for me today – thanks everyone! Here’s another critical juncture where Mark presents and the readers rise to the occasion and I go from “I can’t do that” to “Hmm, there’s something here to try”. Lingering hamstrings angst from cardio-queen days. I did cold baths a few times, definitely helped but I dreaded it so much I stopped. But all these posts are so affirming, there’s something here to glom onto, perhaps the final missing link to healing… Psyched for the series, can’t wait to see how this progresses.

  33. Okay, I’ll be a guinea pig :). I’ll do 20 minutes in my old clawfoot tub full of cold water 4x a week. I hope to lose some body fat and/or help my immune system. We’ll see!

  34. a book, “survival of the sickest,” theorizes that some common diseases had an evolutionary benefit.
    The benefit of diabetes, of having excess sugar in the bloodstream, is that in extreme cold, cells will freeze at a lower temp.

    I wonder if plunging into extreme cold often and for long sessions is asking the body to adapt to extreme cold? One way is to burn fat for heat. Another is to allow more sugar to circulate in the blood. Just a thought.

    1. “I wonder if plunging into extreme cold often and for long sessions is asking the body to adapt to extreme cold?”

      Yes, i believe it is. Like most things, our body gets used to certain set point and in order to achieve the same effects as before, one must alter the factors. From my understanding, the same applies with cold exposure.

  35. I do water aerobics twice a week — the pool is cool-ish (but not cold, alas) and the room is just horribly hot (GA in the coming-onto-summer). The locker room feels very cold afterwards, so I used to take a warm shower. Now, I start off warm and turn the water down (pretty quickly) as my skin adapts. LOVE it! I don’t want to get out, even when it’s down to all-cold. Too soon yet to see any real effects, other than just really liking it. But for those recoiling: try starting out at your normal shower temp and then lowering the temp.

  36. Ok really hard to do cold plunges when you live in the desert. During the summer my cold water is over 100 degrees….

  37. Come to Santa Rosa, NM. Bluehole is 65 degrees year round and when it’s ninety-five plus out, diving in there is quite a zinger!

  38. Whenever i do cold icebaths (50 degrees for hips Down for 8 minutes) i get extremely internally cold for extended periods after. Even after i change my lips will be blue for an hour later. Any suggestions to still reap the benefits ?

    1. Simple: don’t expose yourself to such cold temperatures. Gradually build-up to colder temps. You want to trigger an acute stress response. You do not want to overdo it.

  39. Does anyone have any tips for where to start if you are starting from scratch? It can seem overwhelming to pick one thing when there is so much to choose from. Thanks!

    1. Here’s one suggestion – start with taking a hot shower (for as long as you like), then switching to cold for 30 seconds. Alternate from hot to 30 seconds of cold 2 or 3 times a shower.

      After a week or two, once you get used to it, try just starting with a minute or more of cold shower before switching to hot (or just getting out).

      Once the cold showers start to feel easy, then you can move to experimenting with immersion in cold water….

      The idea is to give yourself a healthy stress, and increase exposure only to the level where it still feels healthy/energizing. Hope that helps!

      1. Thanks markkuto! Does it matter how cold the water is? I find taking cold (ish) showers are more difficult than jumping in the ocean or pool. But its not “on its way” to summer in FL, it feels very much like summer 🙂 The pools and oceans are heating up..

        1. In my understanding, it’s best to just start by lowering the temperature of the cold cycle in the shower to as cold as you can take it while remaining (relatively) comfortable. Try to keep breathing and relax. Over time, you will be able to go colder and longer while staying comfortable.
          Yes, I think how cold the water is matters. Colder water is better for some purposes, especially toning the cardiovascular system in response to cold stress. I’ve worked my way up to ice baths and (alas!) the colder temps give a greater effect. But that might not be necessary for some of the other benefits (like thermogenesis and fat loss) other folks are talking about here – that’s just my experience with my own goals. I also live in Vermont and I’m interested in increasing my cold tolerance so I can have more fun playing outside for long hours in the winter!

  40. I have to say I really, really hate cold water. While I find it possible – just – to sit in cold water just over my hips for five minutes I just cannot bring myself to lie down in it. My body, despite my best intentions, just won’t do it.

    So… Perhaps if I just try to lie down in 2 cm of cold water for 10 minutes. Then add a cm a day, that might be doable. Ummm… Perhaps I’d better go and do it now as if I put it off today, I’ll put it off tomorrow and tomorrow.

    1. Turned out I just couldn’t get myself to lie down in 60 degree cold water. So as a first step it was 11 cm of 76 degree water and I managed it for about 10 minutes. My hands and feet are just so cold though my legs are starting to warm up.

      I really, really want to improve my immune system and lose another 10 kg of weight. But it has to be doable, and straight cold water baths aren’t – yet.

      1. Start smaller. Baby steps.

        Simply spray your legs with cold water after a warm shower or bath. Gradually increase the time that you spray your legs. You can even begin by just spraying your lower legs and build up to your upper legs and ass.

  41. I have burning question that I would like everyone’s do you all count carbs? What if I made chili or soup or kale and onion sauté how would I count the carbs per serving? I’m so confused?

    1. I really wouldn’t worry about the carbs in non-starchy veg. In the big picture, they really are insignificant.

      Just make good food choices and the carbs will limit themselves. Easy.

      Constantly counting quantities is not sustainable and if it is, it is not enjoyable.

      At any rate, here is a good site for nutritional information on all kinds of foods:

    2. I both agree and disagree with Brad. After a couple of months you will be comfortable with your body that you can heed Brad’s advice.

      Early on though, carefully understanding the ingredients is very important. I know I was shocked to see how many carbs, and in particular the glucose load, were in foods I thought was healthy.

      Use I just looked up sauted onion and kale —
      Kale 7.4g per cup (2.6 Fiber) and Onion 6.8g per cup (1.5 Fiber). So you can eat a lot of that.

      For Chili, you will need to look up the ingredients you add to the chili. But Fit day has a nice feature where you can add all the ingredients to your “meal” and get the summary data.

  42. I had to do cold water immersion as a part of first responder ice rescue training. 3 minutes in 35 degree water. There is such a thing as water too cold and too long of an immersion. That was it. I believe in cold water on my legs after I run. They feel better. But the polar bear plunges? I’m never doing that again.

  43. I personally have always enjoyed the invigoration brought on by cold water. I have experimented with it and dont know that it has done me a lot of good but I also havent been very strict with it. I appreciate the fact that you mntioned confounding variables. I think that in the Ancestral health community where self experimentaion is pretty common people tend to forget about confounding variables and conformational bias when giving reports and advice from their own experimentation.

  44. funny, i workout in the little gym at my apartments and it’s located right by the shared pool. nearing the end of my workout, i crave just diving into the pool. interesting………………………………

  45. Have only seen one person mentioning it briefly in the thread, so I’ll bring this one up.
    For as long as I can remember, I’ve been extremely cold sensitive. I’m a native of Sweden, having grown up with asthma, eczema and allergies, the unholy trinity it seems, of until recently ,undiagnosed food allergies. The cold and dry air of the winter months were, and still are, a huge eczema trigger.
    Now, I’ve spent 6 of the last 8 years in sub-tropical and tropical climates, with periods of staying back in the cold north. I’m currently back for a while, and Sweden has had the coldest month of June so far since 1928 (I think it was). So I notice how much more cold sensitive I still am compared to the rest of my family and friends, feeling the need to wear a jacket or at least a thick sweater inside the house of my sister, trembling as soon the as clouds block the sunlight. For me, the greatest allure of cold plunges, since I saw it starting to be discussed in these circles, has been the potential for decreasing cold sensitivity and heat generation in general. I’m curious about other people’s experience of this. Has anyone here experienced increased ease with lower temperatures since starting a cold plunge routine?
    Having access to a sauna, as well as a jacuzzi and well-water below 10 degrees celsius, I decided to give the cold plunge a chance a few days ago. It had to be after coming out of the sauna though, as there is no way I get into an icing cold tub of water if I don’t feel an urgent need to cool down. Unfortunately, I had caught a cold on the flight home, which was worsened a bit by this unexpected stressor, but I aim to keep trying when I get back to my parents’ house. I guess what I’d like to know is:
    1: Are there any serious risks for a generally healthy (save the asthma/eczema/allergy bit) 28-year-old male to go straight from the sauna into a tub full of cold water?
    2: What are the chances that this will help me sort out my cold tolerance? For that is really my main goal with this experiment.
    3. Might it also have an effect on my eczema and my skins tolerance for lower air humidity?

    I’m happy to see a balanced and good post on the subject, and I really appreciate your balanced approach to n=1 experimentation and the scientific method applied in daily life Mark, thanks again!

    1. Yes, I’ve been doing this since March and my tolerance for cold has gone way up. I now feel comfy indoors at temps as low as 60 with bare feet and a t-shirt. One of the first signs of becoming cold adapted is waking up in the night really hot and sleeping without blankets. I started slowly in a tub of 80 deg water and lowered the temp by 1 deg a day. It didn’t take long to feel like I could jump the temp down even more. Now I’m just as comfortable in 50 deg. water as I was that first day in 80.

  46. I haven’t gone too far with cold plunges. However, I have worked nights for the last three months and as such find it harder to sleep during the day than at night. That’s even with black out curtains and a sleeping mask. However, I started trying to take cold showers before bed and I have found for me that I get to sleep way easier and sleep way better for the day. It seems I sleep a longer more unbroken sleep. I am just putting this out there if anyone wants to try the same thing. I should like to experiment with cold shower after working out and see how my recovery goes.

  47. I’m a scientific data kind of guy, who also likes the edge of being different, so I will definitely enjoy this series!
    Now, time for some journaling and cold plunges!
    I work at a butcher shop so a nice break in the quick freeze should be nice too.

  48. I always soak in icy-cold bathwater when I’m super stressed. I’ll even run the water over my feet while the tub is filling. Calms me down like nothing else.

  49. As a marathon runner I am an absolute believer in the value of ice-baths following prolonged exercise.

    The purpose is to reduce cell necrosis, a process whereby micro-tears in muscle fibres release toxins that in turn damage and kill surrounding cells, thereby setting up a self-propagating process. At a macroscopic scale we experience the result as soreness, stiffness and inflammation.

    However, if you spend 10 minutes immersed in water below 10C (50F), within 60 minutes of completing your workout, you will drastically slow this process, and should experience a noticeable reduction in soreness – both immediately and on the day following your workout.

    I recently completed an ultra-endurance event that involved running 10 full marathons in 10 days. Part of the post-run routine every day was waist-deep immersion in an ice bath calibrated between 3C and 5C (37F and 41F). We had the luxury of jacuzzi-style bubbles to accentuate the water circulation, and thermostat-controlled temperature to maintain the chill. First 30 seconds were a killer, but after 10 minutes I could feel the benefits, and most importantly I could walk normally again when I got out!

    So anyway, go ahead and give it a shot. You may be surprised!

  50. Hey mark ive had a cold shower every morning for last 3 years. No dramatic effect on weight loss, gives you extra energy (bit of a buzz) for about 15-30 mins, wakes you up like all hell. But the biggest difference. I haven’t had a cold or flu for 3 years. Prior to that I was regular x2 colds per year. I exercised ate heaps of veggies but still got sick. Harden up, take a cold shower don’t get sick. Eventually you get used to them as well…it takes a long while though. 🙂

  51. I shower with cold water and go for cold swims. Helps me cultivate resilience.

    1. Yesterday I resolved to go for a cold swim and frolic in the water. October 10 in the rough waves of Lake Simcoe.
      I started like I usually do, heading straight out from the shore. When my energy waned I tread water, when it waned more I swam back to where I could stand with my head above the water and flexed and thrashed my arms to stay warm, then stood where the water was about chest level and fought the waves.

  52. Oh, and if you want really strong results, be sure to introduce a period where you remove the cold plunges and note the change (or lack thereof) in workout recovery.

    Read more:


    Stopping TRHT (if you’re doing it properly, not just short duration cold ‘plunges’) will not sudenly create a loggable/measurable effect… proper TRHT effects after say 6 months or a year say 5 days/week, will continue benefits at least for 4 or 6 months maybe more, on heart-rate, BP, immuno etc.

    IMHO (read previous posts) short plunging, albeit regular probably won’t develop the same longer term effects as VJ Kakkars TRHT (progressively up to full torso immersion down to 15C for approx 20 minutes after say a month of conditioing)

    Best Rgds, HM

  53. I have been ‘training’ my body with cold water immersion for 3 months now. I began with finishing showers with cold, but not use a 100 gallon tub. I have lost 20 pounds yet have gained muscle in twice weekly weight lifting (upper body one day, lower body another day). Lots of recovery time and found that the sooner I get into the cold water tub weights, the faster my recovery from sore muscles (rids them of post workout lactic acid). So with muscle gain and body weight loss, its hard to estimate fat loss weight. Anyway, I used about 54 to 58 degrees for the tub for over a month, then got into the high 40’s to low 50’s, now am in the low to mid 40’s. I do this 2ice a day! I found early morning before work is best when done SHORT duration (3 or 4 minutes) or you will be tired later on. But after work, before bed, I aim for about 15 minutes each. Post workout, 20 minutes. I love it now, and find it a real triumph to do in the wee hours of the morning. It feels like slaying a dragon! Not for the faint hearted, but will build anyone’s courage if DONE. Soldier into it, don’t just ‘try’ to get in, just ‘do it’ and get it done! AND, one more thing, read the book ‘Eat Right for Your Type’. It is my bible. Our blood types ‘evolved’ by where we were and what we could eat, so our internal bacteria as well as immune system is based to favor certain foods and not others. It was the best thing I have ever done for myself was to follow this book! So, I think, the secret to a long and happy, healthy life, are in these two things; blood type eating, and cold water stresses. ENJOY the multitude of benefits! 🙂

  54. I forgot to add this important note: I am a diabetic using insulin. I can more easily than a non-diabetic, measure changes in my metabolism because I can read my blood sugar levels and see what influences it. A non-diabetic cannot because their pancreas secrets what is required keeping blood sugars within the normal range. So, here is what I found (in keeping with the purpose of these postings; experimenting.
    Weight (fat) loss does increase metabolism, but so does cold water immersion. Although cold water immersion DOES reduce body fat and I have accounted for the corresponding need to either lower my insulin OR eat more, I also find without any doubt, that in the hours following a cold water immersion, even a 3 minute one, my blood sugar falls lower than without the therapy. That is proof right there the metabolic benefits of cold water. I have also notice an increase in testosterone (by way of libido increase), and better sleeps, moods, energy levels and skin appearance!

  55. I have been finishing my hot showers with cold ones for 20 years and over the past couple years I alternate hot/cold plunges in my 2 bathtubs once or twice a month. These are the following benefits I have noticed:

    Faster metabolism
    Stronger immune system (I am never sick!)
    Decreased inflammation
    Faster recovery from injuries
    Clearer skin
    Less headaches
    Increased energy
    Decreased depression
    Calmer and more relaxed state afterwards

    The hotter…and the colder…the better! Be sure to breathe and relax while doing the cold plunge…no tensing up, just relax into it.

    Happy Plunging!

  56. I take 55 min. showers water temp 51.8 degrees. 55 isn’t a special number it just takes that long. I don’t use a shower head or warm water/food/heating/jackets. Iv’e been interested in natural water temperature and avoiding artificial heating/cooling since ’81. To some I appear Obsessed.

    To me the way people live and care for themselves and others is bizarre and totally unhealthy

  57. awesome topic as always, so inspiring, and now 22 minutes have past and I am thankful, hopeful, once again inspired, thanks so much primal peeps I love reading everyone’s views and finding we are all somewhat in tuned. we can take it as far as we want. tonight is going to be so chillin’ pun intended 🙂

  58. It applies to cold for recovery (not fat loss) but the results of a new study accepted for publication in The Journal of Physiology weren’t favorable towards post-exercise cold water immersion for recovery or long term muscle training goals.”Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training”

  59. Seeing a bunch of comments here about less colds and flus, and this has been my experience as well! Especially in winter, which can get quite cold here (Quebec), there is something to be said about cold winter activities like skating, snowshoeing and x-country skiing.

  60. Great post Mark!

    Self experimentation is a great way to internalize your processes. I’ve done cold plunges for a number of years now and decided to do my own self experimentation with them. I realized that if we can boost our mood at the start of the day with a morning routine that we will be able to improve our lives on a daily basis. I tested out 3 “mood improving” protocols and put them together every morning (Cold plunges, drinking water and cardiovascular exercise).

    If you are interested in a quick read about my experiment check out: