According to new research published ahead of print in the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, breathing through the nose leads to several benefits, including lower blood pressure and other factors that could predict heart disease risk. The study was chosen as an APSselect article for January.
A group of 20 young adult volunteers participated in a crossover study consisting of rest and exercise conditions. In the rest condition, the volunteers performed both nasal-only and mouth-only breathing activities in a randomized order. First, they sat quietly for five minutes and then breathed for five minutes at their own pace. Nasal breathing was performed with the lips closed; mouth breathing was done with soft nose clips to prevent nasal airflow.
The exercise condition was meant to mimic the activity of daily living of walking at a moderate pace at a slight incline. The volunteers breathed, also in a randomized order, at their own rate for seven minutes while using a recumbent stationary bike. As with the rest condition, one activity involved mouth-only breathing and the other, nasal-only breathing. The research team measured the volunteers’ blood pressure, blood oxygen levels and heart rate during each condition.
The research team found that the volunteers’ diastolic blood pressure was lower when they breathed through the nose and a lower perceived rate of exertion than when they breathed through the mouth in the rest condition, but not exercise condition. In addition, nasal breathing shifted the nervous system into a more parasympathetic state (“rest and digest” rather than “flight or fight”) during the rest condition.
