Why Do We Yawn And Why Does It Seem Contagious?

Humans, on average, yawn about 5 to 20 times every day, and each yawn lasts about 5 seconds

Yawning is associated with sleep, but it does not indicate a need for sleep, according to scientists

Also, yawning does not mean one has less oxygen in their body or excessive carbon dioxide, as believed by many

Yawning is said to be a form of non-verbal communication. Baboons use this as signal to troops that it’s time to sleep

People yawn when their breathing is shallow, or when they are tired, bored or have just woken up

Yawning stretches out the lungs and nearby tissues, and prevents tiny airways in the lungs from collapsing

Yawning helps increase heart rate, stretches muscles & joints, prepares the body for increased alertness, according to Harvard Medical School

Yawning is an involuntary process that helps cool down the brain, Penn State University article quotes Andrew C Gallup, a researcher in evolutionary psychology

Humans & chimpanzees show contagious yawning, which refers to the urge to yawn on seeing others yawn

Yawning could also be a symptom of a disease such as multiple sclerosis or amyotrophic lateral sclerosis, according to Harvard Medical School

A person may also yawn before they are about to experience a migraine headache

Yawning could also be a means to help one's mind & body transition from one state to another, and not related to how tired they are