Is Wim Hof breathing safe?
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It can be, for a healthy person sitting or lying down, never in or near water and never while driving. The method’s own FAQ says to skip it if you’re pregnant or have epilepsy, coronary heart disease, a history of heart failure or stroke, or high blood pressure you take medicine for.
Wim Hof breathing is easy to find and free, so it looks harmless. The danger is specific. The hold after the fast breaths can make you pass out with no warning, and the harm depends on where you are when it happens.
What we’d do
If none of the health conditions apply to you, do the rounds on a bed, a couch or the floor, where passing out wouldn’t hurt you. Don’t do them in a bath, a pool, a hot tub, the sea or a car, and never as a warm-up for swimming or a cold plunge. If you’re unsure about your heart or blood pressure, ask your doctor first, and use a slow pattern meanwhile.
Why people pass out
The 30 fast, deep breaths blow off carbon dioxide. Carbon dioxide is what drives your urge to breathe, so with less of it the hold afterward feels easy. Your oxygen keeps falling the whole time, and nothing warns you it’s getting low.
It’s like taking the battery out of a smoke alarm. The fire still burns, you just don’t hear it. In a 2014 study of the method, the trained men’s blood oxygen dipped to around 50 percent at times during the breathing. That’s far below the 95 to 100 percent most people sit at.
Why water is the hard rule
A CDC report on New York from 1988 to 2011 found 16 people who blacked out underwater from breath holding, and 4 of them died. All four who died were advanced or expert swimmers aged 17 to 22, and all four had hyperventilated on purpose. Breathing hard first lowers your carbon dioxide and delays the signal to come up for air, the report explains, while oxygen drops until you lose consciousness.
The method itself agrees. Its safety page says “Never attempt the exercises before or during diving, driving, swimming, or taking a bath”. Its breathing page says passing out “can potentially be very dangerous in or near water, or when driving a vehicle”.
Who should skip it
| Condition | Why it’s on the list |
|---|---|
| Pregnancy | The method’s FAQ and safety page both advise against it |
| Epilepsy | Doctors use fast breathing during an EEG to bring on seizure activity |
| Coronary heart disease, heart failure or stroke | On the method’s own list of conditions to avoid it with |
| High blood pressure on medicine | On the method’s own list |
| Kidney failure, cold urticaria, Raynaud’s (type II), recent surgery | Also on the method’s list |
The Epilepsy Foundation describes hyperventilation, “very quick breathing”, as one of the standard ways to bring out seizure discharges on an EEG. That’s why fast rounds are off the table if you have epilepsy.
How well is the safety tested?
It hasn’t been tested much. A 2023 review of breathwork trials found no reported harms that lasted, but most trials were of slow breathing, and the authors asked for more safety research on fast breathwork in particular before it’s offered to vulnerable people. Nobody has reliably counted how many people have been hurt doing it. This site doesn’t have a fast rounds timer yet, for the same reason.
How to do the rounds is in how do you do Wim Hof breathing. Every condition, for every pattern, is in who should skip which breathing exercises.
The Wim Hof method has what each round does to your body and what the famous studies did and didn’t show.
8 sources
- Wim Hof Method, Frequently asked questions, checked 2026-11-14wimhofmethod.com
- Wim Hof Method, Safety warnings, checked 2026-11-14wimhofmethod.com
- Wim Hof Method, Breathing exercises, checked 2026-11-14wimhofmethod.com
- Boyd C et al., Notes from the field: hazardous breath-holding behaviors, New York, 1988 to 2011, MMWR, 2015cdc.gov
- Cleveland Clinic, Blood oxygen levelmy.clevelandclinic.org
- Epilepsy Foundation, EEG, reviewed 2025-06-04epilepsy.com
- Kox M et al., Voluntary activation of the sympathetic nervous system and attenuation of the innate immune response in humans, PNAS, 2014pmc.ncbi.nlm.nih.gov
- Fincham GW et al., Effect of breathwork on stress and mental health: a meta-analysis of randomised-controlled trials, Scientific Reports, 2023pmc.ncbi.nlm.nih.gov
