Wim Hof-Style Breathing and Water: Drowning and Blackout Warnings

The one rule

Never do fast, deep breathing followed by breath-holding in water, near water, or anywhere that fainting could hurt you. That includes pools, lakes, the sea, baths and showers, and also driving and heights. If someone is found unconscious in water, call 911 right away (US). This page gives no breathing instructions.

Why water is the danger

Fast, deep breathing (hyperventilation) lowers carbon dioxide in the blood. Carbon dioxide rising in the blood is what normally triggers the signal to breathe, so with less of it the urge is delayed. [1] In a 2023 experiment with 18 volunteers, 15 seconds of hyperventilation lengthened breath-holds (133 versus 111 seconds), delayed the first involuntary breathing movements, and left oxygen lower after each hold. Oxygen dropped further across repeated holds, which the authors said could heighten the risk of a blackout. [2]

Loss of consciousness can then come with little warning. A UK drowning-research group explains that "hypoxic blackout" means passing out underwater after hyperventilating and holding the breath, and that it does not depend on water depth and can occur in any depth of water. [3] It notes that the American Red Cross, YMCA and USA Swimming now use the term "hypoxic blackout" rather than "shallow water blackout" for this reason. [3] A review of breath-hold diving found that deaths concentrate among less well-trained recreational divers who become short of oxygen. [4]

Cold water adds a second risk. Experts quoted by Live Science explained that cold water can trigger a gasp reflex, and that a single gasp underwater can be enough to cause drowning. They also described a conflict between the heart-slowing response of a face in water and the heart-speeding cold shock response, which could lead to irregular heartbeats. [1]

What has been reported

We could not find a medical case series or registry of Wim Hof-style incidents: proper evidence not found in the PubMed searches we ran for the method name with drowning or loss of consciousness. What exists is news reporting, and it has limits.

• In 2016 a Dutch newspaper reported that at least three people had died after practicing the method while combining breathing with water immersion. [1]
• A journalist told Live Science he had linked 31 deaths to the method from public reports and private accounts. Most were drownings, and none has been confirmed in court to have involved the method. [1]
• A Dutch news site described a dozen drownings linked to the breathing exercises. [5]
• In the first case brought to court, over the 2022 drowning of a 17-year-old girl in California, a judge acquitted Hof for lack of proof. The defense argued the question was whether it could be shown that she was doing the exercises in the pool, not whether the exercises can lead to drowning. [5]

So it is accurate to say deaths have been reported and linked by journalists, and that causation was not established in court in the case reported. It is also accurate that the physiological mechanism of hypoxic blackout is well described. [3]

What the company says

The method's own breathing page says intensive rounds can in rare cases cause loss of consciousness, which is dangerous in or near water or when driving, and says to practice seated or lying down in a neutral space. [6] A spokesperson told Live Science that the company has warned about practicing in water since it heard of drownings in 2015 and that its videos are not the official method. Critics note that videos of Hof submerged send a mixed message. [1][5]

Who is most at risk

An expert told Live Science that hyperventilation alone can make people pass out. [1] NCCIH notes rare reports that relaxation techniques worsened symptoms in people with epilepsy, certain psychiatric conditions, or a history of abuse or trauma. [7] As a precaution, check with a clinician first if you have a heart, lung or blood pressure condition, epilepsy, or are pregnant, and avoid these practices if you have a history of psychosis or mania. See breathwork safety and breathwork, driving, water and heights.

If you want to try something instead

Slow, comfortable breathing carries far lower risk; see breathing exercises for stress. For cold-water practice, which has its own hazards, read hydrotherapy safety before anything else. For the wider picture on this method, see what studies found on the Wim Hof Method, breath-holding challenges and freediving and breath-hold sports.