Yawning is a semi voluntary act characterised by a simultaneous inhalation of air, accompanied by stretch and followed by exhalation of breath. It is often perceived as an indicator for sleepiness, hunger, boredom or fatigue. Yawning can be triggered by sociological, physiological and neurological factors. People yawn for various reasons that may include some of the following:
- To regulate brain temperature
When you yawn cool air is drawn into the body creating a cooling effect in the brain, blood flow to the brain is also increased when the jaw stretches. This is thought to increase the cooling effect.
- Yawning is infectious
Simple daily observations can attest to the fact that yawning is contagious. Yawning is a non-verbal form of communication whereby you can yawn because someone else has yawned; this is because human beings have a tendency of imitating and empathising with other individuals in a social group while communicating.
- Yawning as an arousal mechanism to maintain alertness.
Yawning is an arousal mechanism to maintain alertness and delay the desire to sleep. When you yawn you stretch your jaw muscles, which aid blood flow to the brain, this results in stimulating the brain to consciousness. Yawning brings with it a desire to stretch. Stretching promotes alertness and prepares the body for action.
- Yawning because of neurological stimuli.
Yawning is a respiratory act aided by neurological factors. Chemicals in the brain associated with moods and emotions such as serotonin, dopamine, glutamine and endorphins have been linked to yawning. Increased levels of Serotonin and dopamine have been seen to increase yawning activity while chemicals such as endorphins reduce yawn frequency.
- Yawning as a diagnostic tool in medicine.
Excessive and frequent yawning has been associated with medical conditions such as psychosis and multiple sclerosis and has been perceived as an early indicator of neurological disorder.
While on the other hand the physiological role of yawning has been proposed as an arousal reflex to reverse brain hypoxia.
When yawning always maintain etiquette. Yawning is interpreted differently by different people. Remember that during a yawn your teeth and a large part of your mouth are visible. Depending on your oral hygiene people may see your stained teeth or get a whiff of that not so fresh breath from your mouth. In most communities it is socially acceptable to employ the following rules of etiquette during a yawn:
- Cover your mouth.
- Be discrete.
- Do not yawn out loud.