The Benefits of Wim Hof Breathing

There is a lot of noise around this method, and it does the practice no favours. Wim Hof breathing has some genuinely interesting research behind it and a large body of consistent anecdotal reports. It also attracts claims that would be extraordinary if they were true, and they are not. Here is a reasonable reading of where things stand.

What has actually been studied

The best-known study was published in PNAS in 2014 by Kox and colleagues at Radboud University. Volunteers were trained for ten days in the method — breathing, cold exposure and meditation — and were then injected with an endotoxin from E. coli, which reliably produces flu-like symptoms in healthy people. The trained group produced markedly fewer inflammatory markers and reported milder symptoms than the control group. The researchers observed a surge of adrenaline during the breathing, which appears to be the mechanism.

That result is real and it was a surprise, because the immune response in question was assumed to be entirely outside voluntary control. It is worth being precise about what it shows: trained individuals influenced their acute inflammatory response to a specific challenge, under laboratory conditions. It does not show that the practice prevents colds, treats autoimmune disease, or does anything at all over the long term. Twelve people were in the trained group.

Later work has looked at the method's effects on the brain and on inflammation in various conditions, with results that are suggestive rather than settled. The overall picture: a small, active, generally sympathetic research field, working with small samples, on a practice that plainly does something physiologically measurable.

The effects you can count on

Immediate alertness. This one needs no study; you feel it in your first session. Deep rhythmic breathing raises adrenaline on purpose, and the result is the kind of wakefulness that arrives without caffeine and does not crash afterwards. For many people this alone is why they keep practising.

Warmth. The heat that moves through your hands, face and spine during a session is one of the most reliable effects reported, and it is a large part of why the method pairs so naturally with cold exposure.

A quiet mind, briefly. During the retentions — especially in the last round — there is very little happening. No air, nothing to do, no counting. People who have never got on with sitting meditation often find this is the closest they have come to it, and the stillness usually persists for a while after the session ends.

The effects that are consistent but less proven

Better stress tolerance. This is what long-term practitioners describe most often: not that stressful things stop happening, but that the reaction to them softens. The physiological story is plausible — you are repeatedly creating a controlled stress and meeting it calmly, which is close to how exposure works in other contexts — and the evidence is largely reports rather than trials.

Improved sleep. Frequently reported, though the timing matters enormously. A morning practice seems to help sleep that night; an evening one often does the opposite, because the breathing is stimulating by design.

Focus and mood. Common reports, hard to measure, easily confounded by the fact that people who practise breathing daily are usually doing other things for their wellbeing too. Worth taking seriously as experience; not worth citing as fact.

What to be sceptical about

Anything framed as a cure. Anything that says the method treats a named disease. Claims about "alkalising the blood" as a mechanism for health — the pH shift during breathing is real, temporary, and not the thing doing the work. Promises that longer holds mean better health, which mostly encourage people to push in exactly the way they should not.

Be sceptical, too, of the framing that makes any of this urgent. This is a practice you do for fifteen minutes because it feels good and appears to be good for you. It does not need to be more than that.

What is realistic to expect

In your first session: tingling, warmth, light-headedness, and a distinct lift afterwards. Within a couple of weeks: longer holds without trying, and a session that has become easy to start. Within a month or two of regular practice: the thing most people actually stay for, which is a slightly larger gap between something happening and your reaction to it.

That is a modest description of a practice that costs fifteen minutes a day. It is also, on the current evidence, an honest one.

Breathing exercises are not medical treatment. Never practise in or near water, or while driving. Always sit or lie down. Not suitable during pregnancy, or if you have epilepsy, a heart condition, high blood pressure or a history of fainting — speak with your doctor first.

Sources
Kox M. et al., "Voluntary activation of the sympathetic nervous system and attenuation of the innate immune response in humans", PNAS 111(20), 2014 — https://www.pnas.org/doi/10.1073/pnas.1322174111