Stabilizing Effect of Yawning on Nasal Cycle

The dominant passability of the left or right nostril in terms of nasal air resistance can be classified into 4 main modes. In the first mode, both nostrils are closed and have equal and low air passability. In the second mode, the passability of the right nostril is higher than the left. In the third mode, the passability of the left nostril is higher than the right. In the fourth mode, both nostrils are open and passability of nostrils is equal and high. The first and fourth modes are unstable (with duration- minutes). The second and third modes are stable (with duration-hours). Author presents a yawning as physiological reflex leading to transition from unstable to stable modes.