Nasal breathing during exercise is gaining recognition among runners seeking to improve performance and respiratory health. While traditional advice suggests switching to mouth breathing during strenuous activity, the nose offers distinct physiological mechanisms that enhance oxygen utilization and efficiency. This technique requires an initial period of adaptation but can fundamentally change how the body processes oxygen, particularly during lower-intensity efforts. The practice involves consciously keeping the mouth closed and relying solely on the nasal passages for both inhalation and exhalation.
Unique Physiological Advantages of Nasal Breathing
The nasal passages function as a sophisticated conditioning system for incoming breath. Air inhaled through the nose is filtered by small hairs, which trap airborne particles, pollutants, and pathogens before they reach the lungs. The nasal cavity also warms and humidifies the air, reducing irritation to the lower respiratory tract, a benefit noticeable when running in cold or dry conditions.
A biological advantage of nasal breathing is the production of Nitric Oxide (NO) within the paranasal sinuses. This gas is a potent vasodilator, widening blood vessels and improving circulation. When inhaled into the lungs, Nitric Oxide increases blood flow to the alveoli, maximizing the transfer of oxygen into the bloodstream. This effect enhances oxygen uptake, making each breath more productive than mouth breathing alone.
Impact on Running Performance and Intensity Levels
Nasal breathing restricts airflow, limiting the volume of air taken in compared to mouth breathing. This restriction means the technique is best suited for steady-state, aerobic exercise, often referred to as Zone 2 running. During these lower-intensity efforts, the slight reduction in air volume is compensated for by the improved oxygen efficiency and delivery provided by the nasal passages.
This slower, controlled breathing pattern helps the body build a higher tolerance for carbon dioxide (CO2). Rapid and shallow breathing causes excessive CO2 to be exhaled, which can reduce oxygen release to the muscles. The presence of CO2 triggers the Bohr effect, where hemoglobin releases bound oxygen into active tissues. By retaining a slightly higher level of CO2 through nasal restriction, more oxygen is made available to the working muscles, improving running economy.
For high-intensity efforts, such as sprinting or hill repeats, the body’s immediate oxygen demand typically exceeds the maximum airflow capacity of the nasal passages. In these anaerobic zones, the body requires a high volume of air instantly, making the switch to oronasal breathing (mouth and nose) necessary. However, with consistent training, some runners have demonstrated the ability to maintain their maximal oxygen consumption (VO2 max) while using nasal breathing, suggesting the technique’s limitations can be pushed higher over time.
Techniques for Transitioning to Nasal Running
Adopting nasal breathing requires a gradual approach, starting with low-effort activities to allow the respiratory system to adapt. Begin by practicing the technique during walking or slow jogging to establish a comfortable rhythm without the stress of high intensity. The initial feeling of “air hunger” or slight breathlessness is normal and indicates the body is adjusting to higher CO2 levels.
Runners can utilize rhythmic breathing patterns, coordinating steps with breaths to maintain a consistent flow. A common starting pattern for easy running is a 3:3 rhythm: inhaling for three footstrikes and exhaling for three footstrikes, all through the nose. As the pace increases, this can be condensed to a 2:2 rhythm for moderate efforts. This coordination helps regulate breathing and keeps the body relaxed.
To improve CO2 tolerance, runners can incorporate breath-holding exercises into their daily routine, such as holds after a gentle exhalation while walking. These drills condition the body to cope with air hunger, translating to a calmer, more efficient breathing pattern during the run. Runners should revert to mouth breathing immediately if they experience lightheadedness or severe distress, reserving the nasal technique for times when the pace is comfortable and sustainable.