Why is breathing through nose important?

Nasal breathing is useful because it does more than bring air in:

• Filters and defends: Nasal hairs, mucus, and the nasal microbiome help trap or fight incoming pathogens; nasal breathing also supports the nasal environment that helps protect against respiratory infections. 1 2
• Prepares air for the lungs: The nose warms and moisturizes inhaled air, and nasal airflow creates more resistance that can help inflate the lungs. 3
• Supports nitric oxide and circulation: Nitric oxide is produced in the nasal passages and can relax blood-vessel smooth muscle, supporting blood flow. 4
• May benefit sleep and hormones: The discussion links nasal breathing during sleep with less apnea and better sleep, which supports testosterone and estrogen regulation. 5
• Can influence cognition: Research discussed in the show found nasal inhalation was associated with quicker detection of stimuli, and a guest described nasal breathing as shaping cognitive processing. 6 7

In general, breathe through your nose when practical; the show notes exceptions such as speaking, eating, or exercising hard. 8