# Nasal Breathing in Sport: What the Physiology Says

> Most athletes breathe through the mouth under exertion. What the physiology of nasal breathing describes and the role nitric oxide plays in it.

The question of whether nasal breathing offers advantages over mouth breathing in sport is complex and often presented in oversimplified terms. Yet the physiological mechanisms behind nasal breathing are key to understanding its potential benefits and limits. It is not about rigid dogma but about adapting to the body's specific demands.

## Physiological benefits of nasal breathing

The nose is far more than just an air duct; it performs essential functions that the mouth cannot. It **filters** inhaled air, removing particles, pollen and pathogens through nasal hairs and mucous membranes. At the same time, it **warms and humidifies** the air to body temperature and nearly 100% relative humidity before it reaches the sensitive airways. This protects the bronchial mucosa from irritation caused by cold, dry air.

## Nitric oxide and airway dilation

Another important aspect is the production of **nitric oxide (NO)** in the paranasal sinuses. During nasal breathing, this NO is transported into the deep airways, where it has **vasodilatory** (blood vessel widening) and **bronchodilatory** (airway widening) effects. This can improve oxygen uptake. NO also has **antimicrobial properties** that inhibit viruses and bacteria in the upper airways. This protective mechanism is inactive during mouth breathing.

## Airway resistance and training intensity

The **higher airway resistance** of the nose is physiologically intentional and trains the respiratory muscles. At low to moderate intensity, this is beneficial. At very high training intensity, however, when a large breathing volume is required, the nose's cross-section can become a limiting factor. In such cases, switching to mouth breathing or combined nose-mouth breathing is physiologically necessary and sensible to ensure oxygen supply.

## Frequently asked questions

**Why is nasal breathing better in sport?**
Nasal breathing filters, warms and humidifies the air before it reaches the lungs. It also releases nitric oxide, which widens the airways and has antimicrobial properties.

**When should you breathe through the mouth during sport?**
At very high intensity or maximum effort, mouth breathing is necessary, because airflow through the nose is insufficient to meet the body's oxygen demand. Combined breathing is then often the best solution.

**Can nasal strips improve breathing?**
Yes, **[WOO® Nasal Strips](/en/shop/woo-nasal-strips)** can mechanically widen the nasal airway and thus reduce airway resistance. This is particularly beneficial for people with narrow nasal passages or for snoring.

**WOO® Nasal Strips** are a drug-free option for mechanically widening the nasal airway and making breathing easier. They can improve airflow through the nose and thus support the benefits of nasal breathing. Available in our shop.

## Sources

Lundberg JO et al. (2009), Nitric Oxide - Inorganic nitrate and the role of the nitrate-nitrite-NO pathway in human health.
Dallam GM et al. (2018), J Sports Med - Nasal vs. oral breathing during aerobic exercise.
Tanaka Y et al. (2000), Rhinology - Nasal airflow resistance and maximum exercise capacity.

*WOO® Nasal Strips in the NEMAPO Shop.*