Breathing and Relaxation Basics: Slow Breathing, Nasal vs Mouth Breathing and Breathwork Claims

Breathing and relaxation

Breathing is automatic, but it is also one of the few body functions you can change on purpose. That is why breathing sits at the center of many relaxation practices. The U.S. National Center for Complementary and Integrative Health (NCCIH) describes relaxation techniques as practices meant to bring about the body's "relaxation response," marked by slower breathing, lower blood pressure and a reduced heart rate. It lists breathing exercises, progressive muscle relaxation, guided imagery, autogenic training and biofeedback-assisted relaxation among them. [1]

This page is the starting point for the Breathwork and Relaxation category. Specific how-to practices are on the gentle breathing and relaxation practices page. For the goal-level view of stress, see breathing exercises for stress and relaxation techniques.

Comfortable slow breathing

"Slow breathing" in research usually means fewer than 10 breaths a minute. A 2018 systematic review of 15 studies in healthy people found that slow breathing techniques were linked with higher heart rate variability (the natural beat-to-beat change in heart rate), changes in brain-wave patterns on EEG, and reports of more comfort, relaxation and alertness, and less anxiety, anger and low mood. [2] Those are physiological findings and short-term self-reports. The authors' explanations of why this happens are hypotheses.

The NHS describes a gentle version: let the breath flow into the belly as far as is comfortable, without forcing it, breathe in through the nose and out through the mouth, and keep it gentle and regular. Some people count from 1 to 5 on the way in and out. The NHS suggests at least 5 minutes, and says you get the most benefit by doing it regularly. [3]

The key word is comfortable. Straining to breathe very slowly or very deeply is not what these sources describe, and overbreathing can cause lightheadedness (see breathwork safety). [4]

Nasal vs mouth breathing

Online, nose breathing is often presented as clearly better than mouth breathing. For healthy adults practicing relaxation, proper evidence not found in what we could read: we searched PubMed and the web for a systematic review comparing the two and found none. Claims here are mostly marketing claims or based on small studies.

What the research does show is narrower. Blocked nasal airflow was linked with a clinically significant increase in sleep apnea indicators in a 2026 meta-analysis, so a blocked nose is a medical question, not a breathing-technique question. [5] Taping the mouth shut at night is a social media trend. A 2025 systematic review of 10 studies (213 patients) found mixed results, including no difference in some studies, and the authors described a potentially serious risk of harm if people do it indiscriminately, including asphyxiation risk with nasal obstruction. [6] We do not recommend it; if you snore, gasp at night or feel unrefreshed, ask a clinician about sleep apnea instead.

The Buteyko method is a named breathing-retraining program. The Cochrane review of breathing exercises for asthma included it in only one trial, plus one trial combined with pranayama, out of 22 studies (see the table below). [7]

Breathwork claims and evidence

"Breathwork" is a loose label covering gentle practices and intense ones. Judge each by its own evidence.

Most breathing trials cannot hide from participants which breathing they are doing, so expectations may affect results. That limits how strongly any of these can be read.

Breath awareness vs breath manipulation

Two different things are called "working with the breath."

• Breath awareness means noticing your breathing without changing it, as in many meditation practices. NCCIH notes that some meditation types involve keeping attention on a sensation such as breathing. [11]
• Breath manipulation means deliberately changing the pace, depth or pauses, as in slow breathing, box breathing or pranayama.

They can feel very different. NCCIH reports occasional negative experiences with relaxation techniques, such as increased anxiety, intrusive thoughts or fear of losing control. [1] If that happens, stop and try a different approach; our page on meditation difficulties covers this.

Safety and when to get help

NCCIH says relaxation techniques are generally considered safe for healthy people, with rare reports of problems in people with epilepsy, certain psychiatric conditions, or a history of abuse or trauma. [1] Persistent or severe anxiety, breathlessness or chest pain need a health professional, not a breathing exercise. See the full category at Breathwork and Relaxation.