Scientist names unusual function of yawning

Yawning before public speaking leads to a reduction of tension in skeletal muscles and release of physical constraints, promoting a feeling of relaxation.

As reported by BAKU.WS, Dr. Valery Litvinov, Doctor of Medical Sciences, told "Gazeta.Ru" about this.

According to the scientist, yawning is a complex neurophysiological act that engages centers of higher nervous activity. When inhibitory processes accumulate in the central nervous system, dopaminergic neurons activate, transmitting a signal to the respiratory center of the brain stem.

This triggers a chain of reactions: a deep inhale, contraction of the diaphragm and intercostal muscles, a momentary breath hold, and a subsequent powerful exhale.

The volume of inhaled air increases approximately four times, which temporarily increases the oxygen content in the blood. Muscle tension enhances blood flow to the heart, increasing heart rate and the volume of pumped blood by a quarter. This process helps "reset" the nervous system and maintain the body's optimal working state.

Answering the question about why people often yawn before a presentation or exam, Valery Litvinov explained: stress causes excessive tension in the muscles of the neck, shoulders, and jaw. At this moment, yawning performs the opposite function - it reduces the tone of the nervous system. Under the influence of serotonin, the excitability of spinal cord neurons decreases, leading to relaxation and reduced anxiety.

According to the same principle, the expert added, evening yawning works as well. It prepares the body for sleep, helping to transition from a state of wakefulness to relaxation. At the same time, brain activity necessary for the dream phase is maintained, but muscle tone and sensitivity to external stimuli are reduced.