From a biological perspective, what causes the feeling of drowsiness and why does it temporarily go away when we stretch or yawn? Is a specific chemical involved?
In: Biology
Basically stretching increases the blood flow of the body and makes it more alert. Additionally it stimulates the nervous system, it provides stimuli and activated the sympathetic nerve system.
Yawning helps us get more oxygen into our blood and also increases blood flow a bit, it also helps cool our bodies.
There’s also speculation that it’s also a social mechanism meant to signify your own energy levels to others and thus coordinate group behavior and signify your alertness or lack there of to others.
Latest Answers