Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
5 Jun

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!

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. 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!

    Dana wrote on June 5th, 2012
    • 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!

      markkuto wrote on June 6th, 2012
      • 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..

        Dana wrote on June 6th, 2012
        • 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!

          markkuto wrote on June 7th, 2012
  2. 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.

    Harriet wrote on June 5th, 2012
    • 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.

      Harriet wrote on June 5th, 2012
      • 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.

        Brad wrote on June 6th, 2012
  3. 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?

    Danielle wrote on June 6th, 2012
    • 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:

      Brad wrote on June 6th, 2012
    • 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.

      Chris wrote on June 6th, 2012
  4. 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.

    Brad wrote on June 6th, 2012
  5. 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.

    CMHFFEMT wrote on June 6th, 2012
  6. 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………………………………

    jenna wrote on June 6th, 2012
  7. 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!

    Squirenetic wrote on June 6th, 2012
    • 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.

      PaleoMom wrote on June 8th, 2012
  8. 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.

    Trevor wrote on June 6th, 2012
  9. 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.

    Andrew wrote on June 6th, 2012
  10. 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.

    Michaela wrote on June 6th, 2012
  11. 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!

    Robert Dallison wrote on June 8th, 2012
  12. 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. :)

    Dan wrote on June 20th, 2012
  13. I shower with cold water and go for cold swims. Helps me cultivate resilience.

    Animanarchy wrote on October 10th, 2012
    • 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.

      Animanarchy wrote on October 11th, 2012
  14. 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

    Harry Mann wrote on January 23rd, 2013
  15. 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! :)

    Andy wrote on September 29th, 2013
  16. 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!

    Andy wrote on September 29th, 2013
  17. 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!

    Ellen wrote on October 13th, 2013
  18. 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

    Robert wrote on December 12th, 2013
  19. All I can say is Wim Hof

    dave wrote on June 24th, 2014
  20. 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 :)

    Angel wrote on June 23rd, 2015
  21. 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”

    Eric wrote on July 26th, 2015
  22. 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.

    Steve wrote on October 8th, 2015

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