TEMPO.CO, Jakarta - Yawning is a sign that your body needs to rest and that you are feeling sleepy. Many people consider it as contagious behavior. But since a long time ago, there is no definite scientific explanation about its cause.

Some people say yawning is due to lack of oxygen. People usually yawn as they feel drowsy or bored but others do so without any reason. As summarized from Prevention, here are four reasons for yawning.

1. Contagious

Yawning is really contagious. Many experts believe we will yawn after seeing others do so as it is a sign of sympathy or social ties. A further study is likely needed to find out why yawning is more easily transmitted in a closed position. The research in 2011 reveals that yawning only spread among family members, friends, and also unknown people.

2. Your brain needs to rest

The latest theory that emerges related reasons of yawning is the brain needs fresh air and rest. Sleep deprivation can also cause its temperature to be hotter hence it needs cooling.

3. Bigger brain

The wider your mouth opens when yawning, it means your brain size gets bigger. Many researchers claim that wide-vaporized mammals have large brains and more brain cells. If yawning indeed to cool down the brain as to give it energy, a larger brain with more cells needs more oxygen to make the people awake.

4. Possible heart attack

Yawning is also associated with heart attacks or even strokes so long it happens too often. A heart attack can stimulate the vagus nerve, which travels through the brain until the stomach, and that causes reactions which can trigger excessive yawning. People with epilepsy and multiple sclerosis reportedly suffer excessive yawning and that the body’s attempt to help deal with the disease.

YAYUK WIDIYARTI