The Wim Hof Method
In March 2000, a man wearing nothing but a swimsuit and goggles set a Guinness World Record by swimming over 188 feet under ice. This was his second attempt. The first time he tried it, his corneas froze and he passed out.
Welcome to the world of Wim Hof, aka the Iceman.
According to Wikipedia, the only Guinness record that Mr. Hof still holds is for running a half marathon barefoot in ice and snow near Oulu, Finland in 2007 (2:16:34). However, Guinness now shows that Hof's record was broken last month by a man named Josef Šálek (1:50:42).
Don't feel sorry for Mr. Hof that he lost his record. The Iceman, now 64, is the centerpiece of a multi-million dollar health empire grounded in the eponymous Wim Hof Method. Videos, books, apps, apparel, even biannual expeditions with the Iceman himself: All of this and more can be easily purchased.
My question is whether you would want it. Would you accept health advice from a man who has climbed most of the way up Mt. Everest shirtless? (Yes, because he could do that? No, because he's nuts?)
In this newsletter I'll be discussing a new review of research on the health benefits of the Wim Hof Method. I was surprised by the findings – and by close look at what the Iceman appears to be selling. He's not the all-knowing guru some of his devotees take him to be. But he's no mere snake oil salesman or obsessive nutjob either. His "method" may even be good for you, if you're careful.
What is the Wim Hof Method (WHM)?
The mainstream view of the Wim Hof Method (WHM) is that it consists of breathing exercises and exposure to cold. You learn a simple technique for inducing mild hyperventilation, you start taking cold showers or ice baths, and you become a healthier person.
This version of the story has been told and retold in the news (New York Times, CNN, etc.) on talk shows (Ellen DeGeneres, Joe Rogan, etc.), and even in a Goop Lab Netflix episode. The actual story is more nuanced, in a way that's important to deciding whether the WHM is beneficial and safe.
Earlier this week I spoke by phone with investigative journalist Scott Carney, author of the 2017 New York Times bestseller "What Doesn't Kill Us" and other work in which Wim Hof plays an essential role.
I can't imagine anyone having a better perspective on this topic than Mr. Carney. Back in 2011, he met Hof on assignment with the intention of exposing the Iceman as a charlatan. Instead, Carney became a convert, eventually hiking up Mt. Kilimanjaro with Hof wearing nothing but shorts and sneakers.
In recent years, Carney has become a critic. As you'll see, he's the best possible kind of critic, because he continues to embrace what he finds beneficial in Hof's teachings while objecting vigorously where there's cause for concern.
One thing Mr. Carney pointed out during our phone call is that there isn't really "a" Wim Hof Method, because Hof has laid out so many different versions over the years.
As the WHM website describes it, the method consists of three "pillars": Breathing exercises, cold exposure, and commitment. Here's how a simple set of instructions would go:
1. Breathing.
Sit or lay down comfortably. Take 30 to 40 deep breaths. Hold your breath one time, as long as you can. Then take one more deep breath and hold for about 10 seconds. Repeat the entire cycle three times.
2. Cold exposure.
At the end of a warm shower, finish with cold water for 30 seconds. Do that for one week. Increase to a full minute of cold water. Continue increasing your cold water exposure until you reach the 10-minute mark. Remain focused and calm.
Cold exposure is the core of the WHM. As Hof once said, "To me, god is cold. I think of the cold as a noble force…bringing me back to the inner nature the way it was meant to be." But in documentaries, in Carney's 2017 bestseller, and in peer-reviewed studies, you can the training carried out in many different ways – standing in snow, immersion in cold water, etc. – and the duration of exposure varies.
Hof likes to say "a cold shower a day keeps the doctor away", so if you take him at his word, that may be all you need.
3. Commitment.
On the website, commitment is pitched as the foundation of the method. Patience, dedication, determination, mindset: A lot of terms are used to describe it. (In some accounts, the third pillar is described as meditation. If you purchase one of the products, you may be taught meditation techniques, motivational strategies, yoga, stress-reduction methods, etc.)
On the website at least, the point seems to be that the WHM requires sustained effort. It's not a magic pill, Hof emphasizes.
In sum, you might say you practice a Wim Hof Method if you do the breathing exercises once or twice a day, take one very cold shower or bath per day, and ensure that when you do, you feel calm and in control of your body.
What is the WHM supposed to do for you?
Everything.
Comb through the WHM website, interviews with the Iceman, and the reports of enthusiastic journalists, and you'll find references to almost every sort of health benefit.
On the website, the language doesn't have too much of a snake-oil feel. It's not "lose 10 pounds in a week", or "get rid of arthritis forever." Rather, you're told to expect incremental progress: Increased energy, improved sleep, reduced stress, better cardiovascular health and immune system functioning. In short, more of the good stuff, less of the bad.
This contrasts sharply with what Mr. Hof himself has to say. He's a loose cannon, one of those earnest, garrulous characters who says much that's sensible and much that isn't.
There's a reason for this discrepancy between the website and the person: Wim Hof is actually not the inventor, owner, or main promoter of the Wim Hof Method.
Hof was originally a sort of circus performer, a guy who did stunts and set records for things like sitting in ice. Between 2011 and 2013, his son Enahm, recognizing a business opportunity, created the website and the rest of the revenue-generating empire, and Enahm continues to be the one who runs the show.
This explains the contrast between the slick, risk-averse marketing of the Wim Hof empire created by the son and the increasingly bold statements of the man himself.
The website (which Wim Hof claims to be unfamiliar with) assures you that the WHM isn't for everyone, results aren't guaranteed, and caution is needed – in short, you see the usual boilerplate health organizations use to reduce the risk of liability.
Meanwhile, Hof spouts an odd mix of science and pseudoscience, saying things like you should use his method, because if you do, "adrenaline will go up 540%, dopamine goes up 250%, and gone are the essential factors causing depression".
One could spend hours unpacking crap like this. Suffice to say that low adrenaline and dopamine aren't the "essential" causes of depression, but even if they were, a temporary spike after cold plunges won't cure this or any other disease.
It's fine when Hof tells Ellen that a cold shower a day keeps the doctor away. That's innocuous and sort of cute. It's not so cute when the Iceman asserts that he can cure disease, or that pharmaceuticals are useless. In our phone interview, Scott Carney told me that he thinks media attention has changed Hof in recent years, making him increasingly confident and "caught up in his own bullshit". I agree. Perhaps the lowest point is Hof's recent claim here that he cured two children with leukemia.
Carney refers to Hof as a sort of cult leader. Indeed, video footage of the Iceman shows a scruffy but extremely charismatic guy who's skilled at connecting with people who want to connect with him. But Hof's charisma could undermine public health if it spurs reliance on techniques that have no actual health benefits. We need to know what the data says about that.
Hof would agree with me. He's voluntarily participated in studies, and I doubt you can get through five minutes of any documentary or interview without hearing him allude to scientific validation of his method. As he once said, "I want [the WHM] to be evidence-based in science." He's not one of those Goopy folks who downplay or ignore the value of research as a source of knowledge.
The new review
This review, co-authored by Drs. Omar Almahayni and Lucy Hammond at Warwick Medical School, was published two weeks ago in the journal PLOS One.
I like this review, because the authors seem competent, impartial, and humble. They're straightforward about what the data shows, and they don't claim any special insights.
The review included nine peer-reviewed studies published between 2014 and 2022, the only ones the authors could find that systematically explore the impact of the WHM.
Five the studies looked at one or two versions of the breathing exercise, while four looked at a combination of breathing and some sort of cold shower regimen. Outcome variables differed from study to study (biochemical markers of stress and inflammatory response, respiratory changes, blood gas levels, etc.).
We're off to a rocky start. In a review like this, the hope is that you can draw together individual studies and come up with a synthesis. That's not possible when the studies don't look at the same version of an intervention or the same outcomes.
An additional limitation is that sample sizes were small (mostly 15 to 20 participants), and two of the studies merely present additional analyses of previously published data. What we're left with, in effect, is seven separate studies that don't lend themselves well to synthesis.
Looking at the studies individually, most showed strong signs of bias and, at best, mixed results. But Almahayni and Hammond also found evidence that the WHM can reduce inflammation. This is where we see some small but genuinely good news.
Inflammation
Inflammation is a healthy response to injury, infection, or the presence of a foreign object in your body. When one of these events occurs, your immune system sends molecules that promote healing through the bloodstream to the damaged area, and swelling ensues.
Chronic inflammation is unhealthy. It contributes to diabetes, rheumatoid arthritis, some types of cardiovascular disease and cancer, and many other health problems depending on where the inflammation occurs and how long it lasts. Taken together, inflammation-related diseases are the leading cause of death around the world. Any safe means of reducing chronic inflammation would be desirable.
Inflammation and the WHM
In the new review, most of the inflammation-related data comes from three small studies conducted by a Radboud University team.
The latest of the Radboud University publications, which appeared in Psychosomatic Medicine in 2022, improves upon earlier ones, so I'll share a few details here.
The article reports two studies. The first one focused exclusively on WHM breathing exercises. The researchers wanted to know whether short training (one 2-hour session) would be as effective as extensive training (2 hours per day for four days).
The researchers also compared participants trained by Wim Hof versus those trained by a different person. (It's important to separate the effects of the trainer from the effects of the training – The WHM wouldn't be very useful if it only works when the Iceman teaches it live.)
The 40 male participants in this study were divided evenly across two trainings (short vs. extensive) and two trainers (Hof vs. someone else). The main finding was that regardless of trainer and duration of training, participants' blood adrenaline levels rose by a comparable amount after practicing the breathing. This is a biochemical change linked to reduced inflammation.
Although it's good news that the breathing exercises produced an anti-inflammatory response, there was a depletion effect: The change in adrenaline was observed during initial testing but not later in the day. The researchers glossed over the depletion, but it remains a critically important detail. We can't tell from this study (or any of the others) whether the WHM produces net gains in adrenaline levels that would sustain an anti-inflammatory response over time.
You can practice the WHM all you want, but it's not going to reduce chronic inflammation if the method only spurs temporary gains that are lost as your body readjusts. Sisyphus will not get the rock up the hill if he moves it a few inches but then it rolls back into place while he rests.
The second study looked at whether breathing exercises or cold exposure are more effective at producing anti-inflammatory responses. 48 males were evenly divided across four groups: training in breathing, training in cold exposure, training in a combination of the two, and a control group that received no training.
What happened next may sound a little gross, but it was done under carefully monitored conditions: Participants were injected with a small amount of e coli endotoxin.
A common misunderstanding about this study, as well as earlier versions, is that it tests how well the WHM prevents an e coli infection. Hof himself often boasts about how his method kills infection, or that he and his trainees are the only ones who ever proved resistant to e coli.
Actually, the e coli used in this study was an extract that cannot infect anyone. It only produces inflammatory responses, including mild flu-like symptoms as well as biochemical changes that objectively indicate inflammation (e.g., changes in cytokine levels).
The main finding was that breathing exercises and cold exposure each reduced symptoms and biomarkers of inflammation, but the combination of the two techniques was even more effective. This corroborates earlier findings from the Radboud team obtained with smaller samples and weaker methodologies.
In my view, this is the only credible scientific evidence that the WHM has health benefits. Basically, it's promising news from a pair of small studies.
Should you try the WHM?
Sure, but here are some thoughts to keep in mind:
1. The current data are weak.
A few small-sample studies from the same lab show that the WHM reduces inflammation. Even the experts who laud the studies tend to refer to the data as "promising", or calling for further investigation. The WHM may have other benefits, but there's no clear scientific evidence yet that it does.
2. The inflammation-related effects are short-term.
None of the studies show whether practicing some version of the WHM can reduce chronic inflammation. Short-term effects have been observed, but the WHM would have no hope of preventing inflammation-related diseases unless the effects endure.
3. The benefits may only be prophylactic.
At the moment, the most generous reading of the evidence is that the WHM might make you healthier and more resistant to disease. In spite of what the Iceman often says now, there's zero evidence that it cures anything. As Scott Carney told me, he still practices the WHM but "If I ever get cancer, I am going to talk to my doctor."
4. The methods may not be distinctive.
To a biologist, it's impressive that something like breathing exercises can change an autonomic nervous system function such as inflammatory response. Ordinarily that's not possible without medication.
For the rest of us, we should remember that other lifestyle interventions, such as healthier eating, reduced stress, more exercise, and better sleep, have been repeatedly shown to reduce chronic inflammation. So far, the best we can say about the WHM is that it reduces inflammation in the short-term. This raises the question of whether anyone really needs the method, given that long-term strategies are available.
5. The WHM can be dangerous.
Scott Carney points out that Hof often demonstrates his method via a cold water plunge immediately after the breathing exercises. Or he does the breathing while in the water. In one documentary, for instance, you can see Hof in the water saying "I'm in the water, and I do my deep experienced breathing techniques, staying in the water. It's like deep meditation."
This is a recipe for drowning. Hyperventilation followed by holding one's breath can trigger loss of consciousness. Carney has gathered a montage of clips showing Hof combining breath exercises and cold water plunges anyway.
Although there are now warnings on the website and under the YouTube videos, people don't necessarily read them. Given that Hof does the very thing people are warned not to do, the warnings may actually be perceived as a sort of rule meant to be broken. As Carney told me:
"There's a perception that Wim Hof has a special power, he's an athlete...and you can do it too if you follow his protocols. So [in his actions] there's almost a challenging of the rules...the warning is almost like: Don't be a naysayer, push past your limits."
So far, 32 people have died while practicing the WHM. Most of them were young, athletic men whom Carney describes as "people who liked pushing themselves".
Bottom line: If you practice the WHM, keep the breathing exercises and any cold water immersion separate.
6. Caveat emptor.
Although the WHM can be freely obtained and practiced, much can purchased from the website. If you choose to financially support Innerfire, the company that owns the WHM, keep in mind that its behavior as well as that of WHM devotees has a dark side. Innerfire has rebuffed and threatened people who asked the company to promote safer practices. Scott Carney reports being threatened by his own criticisms of the safety risks. He told me that he maintains a spreadsheet of people who died as a result of using the WHM, but he no longer publishes some of the names because family members were being harassed.
7. And yet...
As I've suggested in this newsletter, a distinction can be made between the company, the man, and the method. Some version of the WHM may indeed be good for you.
Science can't arbitrate every health decision we make. In other newsletters I've discussed the inherent challenges of studying connections between lifestyle and health. Trying to link any particular practice, whether it's the WHM or sitting or moderate alcohol consumption, to some long-term outcome like cardiovascular disease is an extremely imprecise venture. In the end, you might try the WHM and stick with it on the grounds that it makes you feel good. As Scott Carney told me, "I think it has helped me in a number of ways that I don't feel necessary to quantify."
Final thoughts
A 2022 survey found that 17% of Americans trust social media influencers more than doctors for health advice. Unfortunately, those influencers may be saying what companies have paid them to say, or just attempting to say something new, without considering what the science might say. (Castor oil in your navel improves digestion, according to a recent TikTok meme debunked here.)
In contrast, Wim Hof has noted more than once that his methods have been around a long time, but he's the first to "bring them to science." He's not the first really, but kudos to him anyway for at least paying lip service to scientific inquiry and volunteering to be studied.
The data does hint that the WHM is good for you, at least by temporarily reducing inflammation. Fans of the method do report positive experiences. Given that the WHM is free, you might consider joining them. Just don't say that it's scientifically validated. (And don't hyperventilate before you swim!)
Thanks for reading!