Yet Wim is not a genetic freak or Tibetan monk. He is a 52 year old Dutch man without much body fat. He believes that anyone can adapt to the cold and learn to control body temperature.

In this article, I will try to answer two questions:

• How does he do it, and can anyone really do the same?
• Is this basically an impressive stunt, or is there any benefit to learning Wim’s methods?

No stunts.  First, just to be clear about what Wim has been able to accomplish,  take a look at these two short videos:

1. Wim running a half marathon in the north of Finland:

2. Wim swimming 50 meters under arctic ice:

An enjoyable account of Wim’s remarkable adventures and methods is detailed in the book Becoming the Iceman, co-authored by Wim Hof and Justin Rosales.  Rosales is a college student who became so intrigued with Wim’s abilities that he managed to earn enough money washing dishes–while still attending classes–to travel to Europe and learn Wim’s methods.  The chapters alternate between those written by Wim and those by Justin. While their account suffers from a lack of editing and is sprinkled with grammatical errors, the excitement of Wim’s remarkable sense of fearless adventure and Justin’s learning process make this book a real page-turner.

Changing how body temperature is regulated.  How does Wim Hof manage to keep his core body temperature elevated, maintain peripheral circulation, and avoid frostbite and hypothermia?  Nobody knows for sure, but there is no doubt that he does it.  Dr. Kenneth Kamler, an expert on hypothermia, frostbite and high-altitude medicine, who has himself climbed up Everest, has observed that Wim’s trained body responds differently than yours or mine.

The normal response to extreme cold exposure starts in the peripheral blood vessels in the extremities  – the ears, nose, fingers and toes.  Blood flow in the extremities at first increases, in order to stimulate warming.  If the cold exposure is prolonged more than a few minutes, goosebumps and shivering kick in to induce warming of muscles and skin.  But if the exposure continues beyond that, a process of biological “triage” takes place.  To preserve the high priority  organs – brain, heart, digestive tract — the body shuts down blood flow to the extremities to prevent further heat loss. The peripheral veins snap shut to segregate warm interior blood from cold peripheral blood. After all, these extremities have a lot exposed surface area, so cutting them off greatly conserves heat.  But the cost of doing this is frostbite and the irreversible tissue damage that often results if the cold exposure is sustained for more than a brief time.  Finally, when the core temperature falls below 95 F, the various stages of hypothermia set in, ultimately leading to death if sufficiently prolonged.

But Wim, and Tibetan practioners of the ancient art of Tummo, are able to significantly alter this normal process.  As Kamler explains, the key adaptation occurs within the brain during meditation–specifically the yoga and controlled breathing exercises that Wim and the tumo practitioners follow.  Of these exercises, breath retention exercises are key.  As a result, there is a significant activation of blood flow and electrical activity in his frontal cortex and hypothalamus — areas that regulate peripheral nerves and veins involved in the regulation of body temperature.   Normally, the circuit between the hypothalamus and these temperature control circuits is involuntary, governed by the autonomic nervous system. Kamler reasonably speculates that,  through meditation, Wim is able to override the normal function of the hypothalamus, allowing the peripheral veins to remain open and heat the extremities, preventing injury.  He points out that Wim must be generating heat and distributing it more efficiently, but he admits having no idea mechanistically how Wim’s meditative techniques accomplish this.

The monks who practice Tummo are able to tolerate cold, but they do so in a meditative pose, while sitting. They speak of being able to generate an “inner fire”.  Wim Hof’s method has diverged from that of classical Tummo. He has innovated significantly, since he is able to control his body temperature while moving about, in fact while exerting himself under conditions of running, swimming, or high altitude climbing which would be challenging for most people even at ambient temperatures! Yet, while Wim is certainly a one-of-a-kind personality, he is insistent that anyone can apply his techniques. His success in teaching Justin Rosales and others seems to bear that out. More recently, Wim  has devoted himself to training others through seminars and training expeditions.

Other abilities.  Wim’s ability to voluntarily control what what we consider to be automatic, involuntary responses does not stop at tolerance of extreme cold.  He has also learned to tolerate extreme heat, consciously overcome pain and cramping, and even moderate his immune response to endotoxin.  A fuller discussion of these abilities is given in Becoming the Iceman.

Possible benefits.  I’m particularly interested in Wim Hof, because of my own positive experience taking daily cold showers.  As I discussed in my post, Cold Showers, making a daily habit of cold showering results in a remarkable degree of adaptation.  The initial intense discomfort of cold shock rapidly shrinks in both intensity and duration, and the self-heating process of thermogenesis becomes more prominent after only a few weeks of the daily habit.  I’ve found benefits in weight control, mood enhancement, and generalized stress resistance.  I’ve not had any colds since starting cold showers. When my family was suffering with a stomach flu that lasted several days, the net effect on me was a 12 hours of achiness which I slept off on a single night, with none of the nausea that they had.

Could more aggressive exposure to the cold provide benefits that go beyond that of daily cold showers?  Hof and Kamler have suggested that the ability to open up peripheral veins and capillaries may help to enhance more than just temperature regulation.  It likely improves blood circulation overall, particularly in the smaller peripheral vessels. Because there are so few individuals that do what Wim Hof does, there is not yet any body of clinical science regarding the benefits to circulation.  But it is not hard to speculate that cold exposure could be a great way to fend of a wide range of cardiovascular and circulatory maladies.  So it intrigues me.

Total cold water submersion.   Cold showers are great, but what Wim Hof does is far more extreme.  Not only is the temperature of the water significantly colder — 32 F vs. the 55-60 F of my showers — but the total body immersion involves much more extensive skin surface area contact, meaning more rapid heat loss. A few times a year, I go for a brisk 10 minute swim in the ocean.  Here where I live in northern California, the ocean temperatures range between 53 and 60 F, similar to my shower water, and ocean swims are definitely more bracing than the cold showers.

My first experiments.  I want to see if I can up the game beyond cold showers. I first read Tim Ferriss’s account of cold water exposure in his book, The 4-Hour Body.  In his chapter “Ice Age”, he recounts the method of Ray Cronis, a NASA scientist who was able to lose almost 30 pounds of fat — fat, not weight — in 6 weeks, by taking cold walks, cold swims, and by drinking cold water.  Ferris himself tried immersing himself in cold baths — with added ice — for 20 minutes.  But he first heated himself to the point of sweating by consuming a thermogenic cocktail of ephedrine, caffeine and aspirin.  So what Conise and Ferris did doesn’t really approach the level of unmediated cold exposure undertaken by Wim Hof.

I want to see how much I can directly adapt to the cold.  My first effort will be to attempt this without any special meditative technique or breathing method, and certainly without taking any thermogenic medications or supplements, as Ferriss did.  So I did my first experiment today, and here is what I did and what I experienced:

I filled a bath with cold water, which I measured at 58 F (14 C).  I first submerged my legs.  It was painful, so I decided to allow myself to adjust before filling the tub with more water. Fortunately, after about 2.5 minutes, my legs no longer hurt and by 4 minutes they felt a kind of paradoxical warmth and I could wiggle my toes again. So I filled the cold water up to my chest when laying back. I was completely submerged at 9 minutes.  At first, this was very uncomfortable, and I started shivering. I felt some numbness, but that went away and I was comfortable again at  14 minutes. I could easily flex my toes and fingers. I continued laying in the tub, submerged up to my neck. The sensation alternated between shivering and coolness. I stayed in until 20 minutes had passed from the initial plunge.

After I got out of the bath, I felt warmer and tingly at first. But 5 minutes after getting out and drying off, I started feeling very cold and shivering uncontrollably. I was not really expecting that; I thought I would instantly feel warmer, just as I always do after stepping out of a cold shower. But in the book Becoming the Iceman, Justin Rosales and Wim Hof describe a phenomenon they refer to as “the afterdrop”, an experience of getting colder after you emerge from cold water. This is exactly what was happening to me. I needed to  put on warm clothes and move around to fight off the shakes. I was still cold and shivering 30 minutes after emerging from the cold bath, and my fingers were stiff, making it hard to type up my notes.

However, a full hour after finishing the bath I started to feel great. I became warmer throughout the evening, even though it has been a chilly evening. Psychologically, I have been quite alert all evening long. So there is some evidence of adaptation, even though the experience has been quite different than what I would have predicted from my familiar habit of cold showers.

I plan to continue experimenting with cold baths over the coming weeks, varying both the duration and the water temperature.  I’m interested to see how readily I adapt, and what other benefits or problems occur along with the adaptation.

As one form of hydrotherapy, the health benefits of cold water therapy are numerous.  Cold showers provide a gentle form of stress that leads to thermogenesis (internal generation of body heat), turning on the body’s adaptive repair systems to strengthen immunity, enhance pain and stress tolerance, and ward off depression, overcome chronic fatigue syndrome, stop hair loss, and stimulate anti-tumor responses.

Some people advocate starting with a warm shower, and switching over to cool or cold water only at the end of the shower. This is fine, particularly if you are afraid that a pure cold shower would just be too uncomfortable or intolerable.  But I prefer just jumping right in. When you start with cold water, you will experience the phenomenon of cold shock, an involuntary response characterized by a sudden rapid breathing and increased heart rate. This in itself is very beneficial. The extent of cold shock has been shown to decrease with habituation, and exposure to colder water (10C or 50F) appears to be more effective than just cool water (15 C or 59F) in promoting habituation. The habituation itself is what is most beneficial, both objectively and subjectively. There is an analogy here with high intensity resistance exercise and interval training, both of which elevate heart rate and lead to long term adaptations to stress, with improved cardiovascular capacity and athletic performance.

But cold showers provide a different and probably complementary type of habituation to that which results from exercise. A study of winter swimmers compared them with a control group in their physiological response to being immersed in cold water:  Both groups responded to cold water by thermogenesis (internal production of body heat), but the winter swimmers did so by raising their core temperature and did not shiver until much later than the controls, whereas the control subjects responded by shivering to increase their peripheral temperatures. The winter swimmers also tolerated much larger temperature differences and conserved their energy better. Other studies confirm that the benefits of habituation show up only after several weeks of cold showering. For example, adaptation to cold leads to increased output of the beneficial “short term stress” hormones adrenaline and thyroxine, leading to mobilization of fatty acids, and substantial fat loss over a 1-2 week period.

So regular cold showers, like high intensity exercise, and intermittent fasting, appear to provide similar, but not identical hormetic benefits.

But now I’d like to focus on the subjective experience of taking cold showers, something not commented on in many of the studies I’ve read. If you follow my approach and plunge right into a cold shower, you’ll get the initial “cold shock” mentioned above:  a quickened pace of breathing and a pumping heart.  Often I find myself involuntarily smiling or even laughing.  For waking up, this beats caffeine. I keep the water cold the whole time. It helps to brace yourself when entering by gritting your teeth and stiffening your muscles. Go in head first and alternate from back to front to make sure you are getting cold all over, including your hands and arms and any sensitive zones. After about a minute, you’ll find the cold water starts to become more tolerable, and after 2 or 3 minutes you’ll feel your body getting warm by its own efforts. This is thermogenesis. I make a point of staying in the shower until I’m no longer uncomfortable.  I found that at first my hands were the most sensitive part, and now they are no longer as sensitive, so they have habituated.

When I started taking cold showers, I measured the water temperature at around 60 F (16 C), but over time I have reduced this somewhat to 50-55 F (10-13C) as my body has adapted. (You can determine this by bringing into the shower a plastic cup and meat or candy thermometer and collecting some water once the temperature equilibrates).  Of course, depending on where you live and the season, there is a lower limit to how cold you can go, but in general you should be able to get at least as cold as 60F in most places. Also, my cold showers used to be very short, maybe 4 or 5 minutes, but now they last as long as my previous warm showers, perhaps 10 minutes.  I still take the occasional warm shower, perhaps once every week or so, but I prefer the cold ones.

I find that cold showers are great for the mood.  Not only are they physically invigorating, they make you feel alive, vital and ready to take on the day. They stimulate thinking early in the morning. I also believe that they have the effect of slightly raising blood glucose very quickly — by perhaps 10 mg/dl, and thereby have an appetite suppressing effect. Generally, this rise in blood glucose is relatively short in duration, but that’s good enough to prime the pump and get the day started.  This effect of cold showers works well with my practice of skipping breakfast most days and often fasting until dinner.

These effects are apparent with the first cold shower. If you continue the practice for several weeks, you’ll find the psychological benefits are even greater. First and foremost, cold showers appear to have improved my stress tolerance, by buffering emotional reactions. What I mean by this is that bad news, surprises, arguments, or events that would have previously caused a brief surge in adrenaline or an emotional flush, no longer have that effect, or at most have a very attenuated effect.  I think this is a consequence of becoming acclimated to the the adrenaline-producing effect of the cold shock.  A deeper explanation of why cold showers are effective in boosting mood, and why the psychological benefits of cold showers increase the longer and more frequently you take them is addressed in my recent post on the opponent-process theory of emotions.

As with any application of Hormetism, you can experiment with the intensity of cold, the duration, and the frequency of cold showers to improve your tolerance at a tolerable rate.  If you find that your heart is beating uncomfortably fast or you are going numb or experiencing pain of any sort, that’s a good reason to ease into the routine more slowly with water that is not so cold. Check with your doctor first if you have a heart condition, migraines, or pain.  But don’t sell yourself short and rush through a cold shower, because you may find that extending a few more minutes provides the greatest benefits in adapting your body to tolerate stress. Not just cold stress — but physical and emotional stress in general.

January 29, 2012 update:  If you want to take cold showers to the next level, check out this recent article on The Iceman.