Wim Hof Method

A method named after its originator

The Wim Hof Method takes its name from the Dutch athlete Wim Hof. A 2012 case study from Radboud University Nijmegen Medical Centre described its single participant as holding several world records for tolerating extreme cold and as claiming that he could influence his autonomic nervous system, and through it his innate immune response. The authors of the later 2014 trial described the technique as his self-developed method involving meditation, exposure to cold and breathing techniques.

The sources reviewed do not give a verified date for when the method was first taught or named. The 2024 systematic review states in its background that Hof holds 21 Guinness World Records for feats of cold endurance. This is the review's own background statement and was not checked independently for this page.

From a case study to trials

Research on the method began with Hof himself. In the 2012 case study he practiced his technique during an 80-minute full-body ice immersion and during experimental endotoxemia, a laboratory model in which a small dose of bacterial endotoxin (lipopolysaccharide) is injected into a vein to provoke a brief, controlled inflammatory response. His results were compared with a historical cohort of 112 earlier participants at the same institution. A single-person study of this kind cannot show whether the effects can be taught to others.

The same research group then tested whether other people could learn the techniques. Their 2014 trial, published in the Proceedings of the National Academy of Sciences (PNAS), had volunteers trained by Hof and three instructors he had trained, starting with four intensive days in Poland. The 2024 systematic review dates the first study of the method to 2014. Later trials moved beyond healthy volunteers to people with axial spondyloarthritis, spinal cord injury and high depressive symptoms.

The three pillars

Almahayni and Hammond describe the method as resting on three pillars: the Wim Hof breathing method (WHBM), cold therapy and commitment. They summarize the breathing as hyperventilating 30 to 40 times and then holding the breath voluntarily at low lung volume, cold therapy as daily cold showers or sitting in an ice bath, and commitment as the patience and persistence on which the other two rest. Studies use WHM for the full method and WHBM when only the breathing component was taught.

Retention and recovery breath

The method's own instructional page names the breathing phases as a series of 30 deep breaths, a retention phase in which the breath is held after letting the air out, and a recovery breath held for 15 seconds, with the full cycle repeated three to four times. Research papers use more technical labels. The PNAS trial called the exercise cyclic hyperventilation followed by breath retention, and a 2025 trial described the method as intentional short-term stress induced by cyclic hyperventilation and cold exposure.

Distinct from breathwork and cold-water swimming in general

The method overlaps with two wider fields, breathwork and cold-water immersion, but findings do not transfer automatically between them. Almahayni and Hammond excluded studies of similar practices, such as tummo meditation, that were not the method itself. A 2017 review of cold-water immersion covered accidental immersion, open-water swimming and clinical cooling, and concluded that the evidence for the many claims made for cold water varies, with some still at the level of anecdote.

Programs labeled as the Wim Hof Method in research also differ from one another. Some taught only the breathing, some added cold exposure, and some compared versions with and without cold. Training ranged from a single session to several weeks, so results from one protocol describe that protocol and not every practice carrying the name.

The breathing exercise

In the PNAS trial, participants hyperventilated for an average of 30 breaths, breathed out and held the breath for about two to three minutes, then took a deep breath and held it for 10 seconds, repeating the cycle several times. The authors report that practicing the techniques produced intermittent respiratory alkalosis, a rise in blood pH caused by blowing off carbon dioxide, and intermittent hypoxia, a fall in blood oxygen.

Measurements in a crossover study of 15 amateur runners show the size of these changes. Oxygen saturation measured at the finger fell to an average of 60 percent at the end of the breath holds, and end-tidal carbon dioxide values after the final round of fast breathing pointed to respiratory alkalosis, with an estimated rise in arterial pH of about 0.17.

Cold exposure

Cold exposure varies widely between programs. In the 2014 trial, training included standing barefoot in snow for up to 30 minutes, lying bare-chested in snow for 20 minutes, daily dipping or swimming in water at 0 to 1 degrees Celsius for up to several minutes, and hiking a snowy mountain bare-chested at minus 5 to minus 12 degrees Celsius. Later home-based programs used milder exposure. A 2024 trial of midlife women combined the breathing with cold showers, guided by 15-minute daily audio instructions for three weeks.

Commitment, meditation and delivery

The third element is described variously as commitment, mindset, meditation or concentration. The PNAS trial taught a 'third eye' meditation, and a spinal cord injury trial paired the breathing exercises with mindset training, delivered through weekly supervised sessions and daily practice at home. Other programs have been taught in person or remotely. A 2022 study found that the rise in plasma epinephrine after the breathing exercise did not differ according to whether the creator of the method or an independent trainer taught it.

Claims made for the method

The method's originator claimed, according to the 2012 case study, that he could influence his autonomic nervous system and innate immune response. Almahayni and Hammond note that Hof claims several benefits for physical and mental health. The authors of the 2014 trial suggested their findings could have implications for conditions involving excessive or persistent inflammation, such as autoimmune diseases, but this was a hypothesis drawn from a laboratory model, not a tested treatment use.

What practitioners report

A mixed-methods study surveyed 192 UK-based practitioners online, analyzed 132 after exclusions, and interviewed 15. Participants described more positive psychological states, better management of distress and a stronger sense of connectedness. Because these were self-selected practitioners compared with published benchmarks, the study describes how practitioners see the method rather than what it causes.

The same study recorded attitudes toward COVID-19 vaccination. Of the 132 respondents, 73 percent had received or intended to receive a vaccine, below the 96 percent the authors cite for the wider UK population at that time, and some interviewees leaned toward natural health approaches.

Uses that have been studied

Researchers have tested the method or its breathing component for a narrower set of outcomes: the inflammatory response to injected endotoxin in healthy men, inflammation and disease activity in axial spondyloarthritis, depressive symptoms, anxiety and perceived stress, heart and blood vessel measures, exercise performance in runners, and mental and physical health after spinal cord injury. That a use has been studied does not mean it is supported. Results for each are set out under Research and Evidence.

The endotoxin trials

In the 2014 PNAS trial by Kox and colleagues, 24 healthy male volunteers were randomized to 10 days of training (12) or none (12) and then received 2 ng/kg of E. coli endotoxin intravenously. In the trained group, plasma epinephrine rose markedly, interleukin-10 (IL-10) rose faster and higher, TNF-alpha, IL-6 and IL-8 were lower, and flu-like symptoms were milder. The authors noted that the design could not identify which part of the breathing raised epinephrine, and that extension to chronic autoimmune disease was uncertain.

A 2022 follow-up ran two studies. In 40 healthy men, both breathing variants raised epinephrine regardless of training length or trainer. In 48 men given endotoxin, cold training alone did not relevantly change the inflammatory response, the breathing did, and adding cold training enhanced that effect. All were young healthy men.

Systematic review

Almahayni and Hammond (PLOS ONE, 2024) searched two databases for studies from 2014 to July 2022 and included nine papers from eight trials. They concluded that the method may reduce inflammation through raised epinephrine and IL-10, while effects of the breathing on exercise performance were mixed. Seven of eight randomized trials were judged at high concern for bias, mainly because blinding was not possible, and samples were small and mostly male.

Inflammatory and neurological conditions

An open-label proof-of-concept trial randomized 24 people with moderately active axial spondyloarthritis to an 8-week add-on program (13) or a control period (11). Its primary endpoint, safety, showed no significant difference in adverse events. Erythrocyte sedimentation rate and the ASDAS-CRP disease activity score fell in the intervention group, but high-sensitivity C-reactive protein did not change.

A 2026 trial randomized 62 adults with chronic spinal cord injury to 7 weeks of the method with cold exposure, without it, or usual care. The primary outcome, mental health, did not differ between groups. The cold-exposure group reported less pain interference and had lower fasting glucose than usual care. Eight people dropped out of the group without cold exposure.

Mental health, stress and cardiovascular outcomes

A 2024 trial randomized 84 midlife women with high stress and depressive symptoms to the method with cold showers (41) or slow breathing with warm showers (43) for three weeks. Counter to preregistered predictions, both groups had equivalent reductions in depressive symptoms, anxiety and perceived stress, sustained at three months. The method group showed less rumination after daily stressors, and all six dropouts came from it.

A 2023 trial randomized 42 people to 15 days of daily practice or control and found no significant effects on heart rate variability, blood pressure, arterial stiffness, perceived stress, affect or vitality. A 2025 semi-randomized trial of 404 healthy adults compared 29 days of the method with mindfulness meditation; method groups reported greater momentary gains in energy and clarity, with minimal trait differences.

Breath holds in or near water

Hyperventilating before a breath hold lowers the body's carbon dioxide stores, which delays the urge to breathe, while oxygen continues to fall. A report in the US Centers for Disease Control and Prevention's MMWR explains that the resulting drop in arterial oxygen can cause loss of consciousness underwater, called hypoxic blackout. A review of New York State cases from 1988 to 2011 found 16 drowning incidents involving such behaviors, 4 of them fatal, and all four people who died were advanced or expert swimmers who had hyperventilated on purpose.

The method's own instructions state that intense breathing over several rounds can in rare cases lead to loss of consciousness, that passing out can be very dangerous in or near water or when driving, and that the technique should be practiced seated or lying down. The MMWR report does not concern the method by name, but it describes the same sequence of hyperventilation followed by a breath hold.

Low oxygen and respiratory alkalosis

The breathing exercise deliberately produces low blood oxygen and respiratory alkalosis. In the runner study, finger oxygen saturation fell to an average of 60 percent at the end of the breath holds. The method's own instructions describe light-headedness and tingling in the fingers and feet as expected sensations. The sources reviewed do not report how often fainting occurs on land, and they do not establish a verified list of conditions that rule the practice out.

Cold shock and cardiac strain

Sudden immersion in cold water triggers the cold shock response. A 2023 systematic review and meta-analysis describes it as a potentially life-threatening reflex that causes hyperventilation, increases cardiac arrhythmias and raises drowning risk by impairing safety behavior. Pooling 17 groups, it found that the response lessened with repeated immersions, typically after about four, though with variation between studies.

A 2017 review of cold-water immersion examined it as a precursor to drowning, cardiac arrest and hypothermia, alongside its uses in treatment. These hazards apply to cold-water immersion generally. The sources reviewed did not test how the method's breathing interacts with cold shock.

Harms reported in trials and limits of the evidence

Trials have reported few harms, but they were small and mostly enrolled healthy young men. The axial spondyloarthritis trial found no safety signals during the intervention, with one serious adverse event 8 weeks after the program judged unrelated. Dropout was uneven in some trials: all six dropouts in the 2024 trial of midlife women and eight in one arm of the spinal cord injury trial came from method groups. Trials have not been designed to detect rare events such as blackout in water.

People with heart or lung conditions, a history of fainting or seizures, or who are pregnant are not well represented in the trials reviewed, so suitability for them has not been established. The method is not a replacement for assessment or treatment of an illness, and it should not delay necessary care.