Breathwork is generally safe. That is true, and it is also the kind of statement that hides the important detail, because "breathwork" covers techniques as different as sitting quietly extending your exhale and deliberately hyperventilating for thirty minutes until your hands cramp.

Those two things have almost nothing in common physiologically, and they have very different risk profiles. Most safety advice online collapses them into one category and then reassures you about the whole category.

Here is a more useful map: which techniques carry which risks, and who should avoid what.

The Distinction That Matters

Nearly every meaningful safety question resolves once you separate breathwork into two families.

Family 1: Slow, downregulating techniques

Coherent breathing, resonance frequency breathing, extended exhale, physiological sighing, alternate nostril breathing, diaphragmatic breathing.

These slow the breath, usually to around 5 or 6 breaths per minute, and shift the autonomic balance toward parasympathetic activity. CO2 levels stay stable or rise slightly. Blood pressure tends to fall modestly.

Risk profile: very low. These are appropriate for almost everyone, including most people with cardiovascular and respiratory conditions. They are the default recommendation for anyone uncertain.

Family 2: Fast or breath-hold techniques

Wim Hof style cyclic hyperventilation, Tummo, Kapalbhati, Bhastrika, Holotropic and Rebirthing style sessions, and any protocol involving significant breath retention.

These involve either deliberate over-breathing, which sharply lowers CO2 and produces respiratory alkalosis, or extended breath holds, which raise CO2 and lower oxygen. Both produce large, rapid physiological shifts, including changes in cerebral blood flow, blood pH, calcium availability, and sympathetic activation.

Risk profile: meaningfully higher, with genuine contraindications and a real record of adverse events.

When an article says breathwork is safe, it is almost always true of Family 1 and sometimes not true of Family 2.

Slow techniques suit almost everyone; intense ones do not

What Goes Wrong, and Why

Hyperventilation and hypocapnia. Fast over-breathing drives CO2 down. Because CO2 regulates blood pH, this produces alkalosis, which causes tingling in the hands and face, muscle spasm in the hands and feet known as tetany, dizziness, and visual changes. It also constricts cerebral blood vessels, reducing brain blood flow by a substantial margin, which is the main reason people faint during intense sessions.

Most practitioners treat tetany as a sign the technique is working. It is a sign of significant alkalosis.

Breath holds. Retention raises CO2 and lowers oxygen while producing a strong sympathetic surge and blood pressure rise. In people with vascular vulnerability, that combination is the concern.

The water problem. This one deserves emphasis because it kills people who are fit, experienced, and doing nothing obviously reckless. Hyperventilating before a breath hold suppresses the CO2 alarm that normally forces you to breathe, while oxygen continues to fall. In water, you can lose consciousness with no warning urge whatsoever. Shallow water blackout is the mechanism, it is silent, and it is fatal. Never combine any breath technique with water. Not in a pool, not in a bath, not in the ocean.

Absolute Contraindications for Fast and Breath-Hold Techniques

Do not practise cyclic hyperventilation, Kapalbhati, Bhastrika, Tummo, or extended retentions if any of the following apply. For these groups, slow techniques from Family 1 remain appropriate.

Pregnancy. Maternal CO2 levels affect placental blood flow and fetal oxygen delivery. Avoid forceful and breath-hold techniques throughout. Slow breathing is fine and often helpful.
Epilepsy or a seizure disorder. Hyperventilation is used clinically during EEG testing specifically because it provokes seizure activity. This is not a theoretical risk.
Cardiovascular disease, including coronary artery disease, arrhythmias, heart failure, and uncontrolled hypertension. The pressure surges and sympathetic activation are the concern.
History of stroke, aneurysm, or any cerebrovascular condition.
Recent surgery, particularly abdominal, thoracic, eye, or neurosurgical.
Detached retina or glaucoma. Intraocular pressure rises with forceful breathing and straining.
Sickle cell disease. Low oxygen states can precipitate a sickling crisis.
Uncontrolled asthma or significant COPD. Forceful techniques can trigger bronchospasm; retention is poorly tolerated.
Psychosis, bipolar disorder, or a history of dissociative episodes. Intense breathwork can precipitate destabilisation, and altered states are a feature of these protocols rather than a side effect.
Panic disorder. CO2 changes are a well-validated experimental trigger for panic attacks. Slow breathing is often therapeutic here; hyperventilation protocols are close to the opposite.

Use Caution, Get Guidance

Not absolute exclusions, but reasons to start slowly and ideally with professional supervision:

PTSD or significant trauma history. Interoceptive practices can surface trauma responses. This is real and reasonably common in intense sessions. Trauma-informed guidance matters more than technique selection.
Type 1 diabetes, where autonomic neuropathy may alter responses.
Thyroid disorders that are not well controlled.
Osteoporosis, where forceful abdominal techniques carry some risk.
Age over 65, or significant deconditioning, where starting gently is simply sensible.
Currently unwell, particularly with any respiratory infection.

Universal Safety Rules

Never in or near water. The single most important rule in this article.
Never while driving or operating machinery. Lightheadedness during intense practice is common and arrives faster than people expect.
Always sitting or lying down for any fast or breath-hold technique. Never standing. If you faint, you want to already be on the floor.
Tingling and tetany mean stop, not continue. They indicate significant alkalosis, not progress.
Do not push through distress. Anxiety, chest tightness, or a sense of dread during a session is a signal to return to normal breathing.
First time, have someone nearby for intense protocols.

Tips & Common Mistakes

Tips:

Start with Family 1 regardless of your goal. Slow breathing delivers most of the evidence-backed benefits for stress, sleep, blood pressure, and anxiety with almost none of the risk. Intense protocols are not a more advanced version of the same thing; they are a different tool with different effects.
Tell your instructor about conditions and medications before a group session, and be sceptical of any facilitator who does not ask.
Pay attention to medication interactions. If you take blood pressure medication, slow breathing can compound the effect and cause lightheadedness on standing.
Stop and reassess after any adverse experience. Repeating a technique that made you feel unwell, on the assumption it was a release, is how minor events become larger ones.

Common Mistakes:

Assuming natural means safe. Breathing is natural. Deliberately hyperventilating for thirty minutes is not, and it produces measurable changes in blood chemistry and brain perfusion.
Treating adverse symptoms as detox or release. Tetany, dizziness, and fainting have straightforward physiological explanations.
Following online protocols with no screening. Most videos include no contraindication list at all.
Combining techniques with cold exposure while unscreened. Cold plunges add their own cardiovascular load, and the combination amplifies both.
Practising intense techniques daily. These are high-arousal protocols, and daily use can leave people more dysregulated rather than less.

When to Seek Medical Advice

Stop and seek urgent medical attention for chest pain, fainting, a seizure, sudden severe headache, weakness or numbness on one side, difficulty speaking, or vision loss during or after a session.

Speak to a clinician before starting any intense breathwork if you have any condition listed above, are pregnant, take cardiovascular or psychiatric medication, or have had a previous adverse reaction to breathing practice. If you are uncertain which family a technique belongs to, the practical test is simple: if it makes you breathe faster or harder than normal, or asks you to hold your breath, it belongs to Family 2 and deserves the caution described here.

How Vayu Helps

Vayu is built around slow, downregulating breathing, which is deliberate. The techniques with the strongest evidence for stress, sleep, and blood pressure are also the ones with the lowest risk profile, and that is the category the app guides.

The app includes contraindication information alongside its techniques rather than leaving you to discover limits by experiment, and pacing is adjustable so you can work at a rate that is comfortable rather than pushing toward a preset target.

None of that replaces a conversation with your clinician if you have a condition on the lists above.

Download Vayu on iOS or Android →

FAQ

Q: Who should not do breathwork? It depends entirely on the type. Slow downregulating techniques such as coherent breathing or extended exhale are appropriate for almost everyone. Fast techniques and breath holds, including Wim Hof style cyclic hyperventilation, Kapalbhati, Bhastrika, and Tummo, should be avoided in pregnancy, epilepsy, cardiovascular disease, uncontrolled hypertension, history of stroke or aneurysm, glaucoma or retinal detachment, sickle cell disease, uncontrolled asthma, panic disorder, and psychosis or bipolar disorder. Those groups can usually still practise slow breathing safely.

Q: Why do my hands cramp during breathwork? That is tetany, caused by hyperventilation lowering your blood CO2 and raising blood pH, which reduces the availability of free calcium and makes nerves and muscles hyperexcitable. It is commonly described in breathwork settings as energy moving or a release, but it is a straightforward marker of significant respiratory alkalosis and a signal to return to normal breathing rather than to push further.

Q: Is it safe to do breath holds in a swimming pool? No, and this is the most dangerous mistake in breathwork. Hyperventilating before a breath hold suppresses the carbon dioxide signal that normally forces you to breathe, while your oxygen continues to fall, so you can lose consciousness without any warning urge to breathe. This is called shallow water blackout, it kills experienced swimmers every year, and it applies to bathtubs as well as pools. Keep all breath practice on dry land.