Nasal Breathing

Nasal breathing routes air through the nose, where it is filtered, warmed, and humidified before reaching the lungs, and where nasal passages release nitric oxide that may aid airway and vascular function. The added airflow resistance naturally slows and deepens breathing, encouraging a diaphragmatic, lower-rate pattern (Diaphragmatic (Belly) Breathing) associated with better vagal tone.

In practice, nasal breathing is the default for relaxation and low-to-moderate exercise; at high exercise intensities ventilation demand typically exceeds what the nose can supply, so mouth (or oronasal) breathing is recruited (Breathing During Exercise & Lifting). Habitual nasal breathing and "breathe low and slow" cues are central to many breathwork and pranayama systems (Pranayama (Yogic Breathing) Overview). Evidence on performance benefits of forced nasal-only breathing during hard exercise is mixed.

• Nose filters, warms, humidifies air; releases nitric oxide.
• Adds resistance → slower, deeper, more diaphragmatic breathing.
• Default at rest and low-moderate intensity; mouth/oronasal recruited at high intensity.
• Performance benefit of nasal-only breathing in hard exercise is mixed.