Nasal Breathing During Exercise
Nasal-only breathing during exercise increases nitric oxide, improves CO2 tolerance, and naturally regulates intensity to keep you in aerobic zones.
Dosage & Timing
Evidence Strength
3/5 — ModerateModerate evidence. Nasal NO production is well-established (Lundberg et al., 1995). Performance studies show comparable VO2 at lower ventilation rates. CO2 tolerance benefits supported by respiratory physiology.
Overview
Train yourself to breathe exclusively through your nose during low-to-moderate intensity exercise. Nasal breathing increases nitric oxide production (which vasodilates airways and blood vessels), improves CO2 tolerance, and helps you stay in aerobic zones. It also filters, warms, and humidifies air.
How To Do It
Start during warm-up
Begin each session breathing only through your nose during the warm-up phase.
Maintain during steady-state
Keep nasal breathing throughout low-moderate intensity work. If you must open your mouth, you're going too hard.
Build tolerance gradually
In the first weeks, you may need to alternate. Aim to extend nasal-only duration each session.
Use as intensity gauge
Nasal breathing acts as a natural governor — if you can't maintain it, dial back intensity.
The Evidence
Each claim is linked to its source study. Confidence reflects the study design — systematic reviews and RCTs rank highest.
High nitric oxide production in human paranasal sinuses↗
Nasal breathing exposes inhaled air to nitric oxide produced in the paranasal sinuses.
Primary Literature
Who Popularized This
Interactions & Warnings
Contraindications
- ⚠Deviated septum or nasal obstruction
- ⚠Severe asthma during flare-ups
- ⚠High-intensity intervals (switch to mouth breathing)
Interactions
- •Synergistic with Zone 2 training — helps maintain appropriate intensity
Measurable Outcomes
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