The guide

Who should skip which breathing exercises?

By GyroscopeUpdated November 15, 202614 sources

Never do fast rounds or long breath holds in or near water, in the bath or at the wheel, since they can make you pass out without warning. Skip them completely if you’re pregnant or have epilepsy, heart disease or blood pressure you take medicine for. Slow patterns sitting down are fine for most people.

People tend to land on one of two wrong ideas. One is that it’s just breathing, so nothing can go wrong. The other is that breathwork is dangerous, so they avoid all of it. The risk is real, but it sits in a narrow place. It’s in fast rounds and long holds, and above all in where you do them. Five minutes of slow breathing on the couch carries very little risk for most people.

The short list

Why is water the big one?

It comes down to what fast breathing does to the alarm that makes you breathe. That alarm mostly responds to carbon dioxide building up. Normally a healthy person on dry land can’t hold their breath long enough to pass out, because a strong reflex forces the next breath first. Breathe hard beforehand and you lower the carbon dioxide, so the reflex comes late. Oxygen keeps dropping during the hold, and it can run out before you feel any need to breathe.

The American Red Cross, the YMCA and USA Swimming call this “hypoxic blackout,” meaning losing consciousness under water after a breath hold that followed hyperventilating. It can happen in any body of water, at any depth, and survival depends on someone getting you out fast. The Wim Hof Method’s own safety page says, “Never attempt the exercises before or during diving, driving, swimming, or taking a bath.”

That includes the cold plunge. If you get into cold water, breathe normally, as the method’s FAQ says, and keep your rounds for after you’re out and dry.

Why driving?

It’s the same reason. Fast rounds can, in the method’s own words, “in rare cases lead to loss of consciousness.” Lying on a bed, the method’s FAQ says there’s little danger in fainting. In a car it can mean a crash. The same goes for a bike, a ladder or a standing desk. Do rounds sitting or lying down somewhere you can’t fall.

A simple way to picture it

Think of fast rounds the way you think of a strong drink. Plenty of healthy adults have one at home without any trouble. Nobody should have one right before driving or swimming. And for some health conditions, a doctor would tell you to skip it altogether.

Why pregnancy, epilepsy, heart disease and blood pressure medicine?

These come straight from the Wim Hof Method’s FAQ. It advises against the method for anyone with epilepsy, coronary heart disease, high blood pressure treated with prescription medication, or a history of heart failure or stroke, and for anyone who’s pregnant. It also lists kidney failure, Raynaud’s syndrome, cold urticaria and the period right after an operation, some of them because of the cold exposure that goes with the method.

Epilepsy has the clearest reason. Fast breathing turns the blood more alkaline, and in children with absence epilepsy, breathing hard on purpose sets off a seizure in 87 to 100 percent of them. The FAQ doesn’t spell out its reasons for the rest. We haven’t found any trial that tested fast rounds in these groups, and the method itself says not to.

Who were the trials tested on?

The evidence for slow breathing comes from fairly healthy adults. The Stanford trial kept out people with heart disease, glaucoma, a history of seizures, psychosis, bipolar disorder, suicidal thoughts or substance use problems, and anyone pregnant. The 2026 Warsaw trial kept out people with chronic diseases, people on medicines for the brain, heart or blood vessels, and anyone pregnant.

That doesn’t make slow breathing risky for those groups, but the trials can’t tell you much about how it goes for them. If you’re in one, it’s a good idea to check with your doctor, and to start slow and short.

The 2023 review of breathing trials found no serious harms reported, but only four trials actively looked for them. Its authors asked for more research on the safety of fast breathing in particular.

Can slow patterns cause problems?

A few things can come up.

• Lightheaded on holds. Box and 4-7-8 have holds. Dr. Weil says a little lightheadedness at first with 4-7-8 is normal and passes. If it doesn’t, shorten the holds or switch to six a minute, which has none.
• Breathing too deep. Slow doesn’t mean huge. Big, deep, slow breaths can still blow off too much carbon dioxide, which brings on the same tingling and dizziness as fast breathing. If that happens, breathe smaller.
• Feeling more anxious. Paying close attention to your body can make some people more aware of a racing heart or tight chest, and that can feel like panic. Make the out-breath longer, the in-breath smaller, and stop if it doesn’t settle. Can breathing exercises make anxiety worse?
• Asthma or COPD. Keep your inhaler plan exactly as your doctor prescribed it. A breathing practice isn’t a replacement for it. Stop if a session leaves you short of breath.

Two old habits to drop

• Taping your mouth shut at night. A 2025 review of 10 small studies found little benefit, and four of them warned of a risk of suffocation if your nose is blocked. Taping your mouth makes you breathe better.
• Breathing into a paper bag. In 1989 an emergency doctor at UC San Francisco reported three deaths in people given a paper bag who turned out to be short of oxygen or having heart trouble. Breathe into a paper bag when you panic.

When breathing isn’t the fix

Breathing practice is for how you feel day to day. Some breathing problems need a doctor.

If you’re breathing fast for the first time and don’t know why, MedlinePlus says it may be a medical emergency and you should get to an emergency room. If you have chest pain, fainting, or trouble breathing that doesn’t settle, call emergency services. If you get short of breath at rest, or snore heavily and have been told you stop breathing at night, see a doctor.

This guide is written for adults. Children resonate at a faster pace than adults (6.5 to 9.5 breaths a minute against 4.5 to 6.5), so adult counts don’t fit them well. Ask a pediatrician before teaching a child holds or fast breathing.