Why Do We Yawn?

The Science behind yawning.

2 min readJun 6, 2021

Photo by Sammy Williams on Unsplash

What’s the first thing that comes to your mind when someone mentions yawning? It’s most probably memories of going to bed tired and yawning. Or being forced to get out of bed earlier than expected one day. You might also remember yawning when a friend yawned, or certain cultural superstitions that are attached to yawning. When we yawn, we pull in a deep breath. Our muscles contract, our backs arch a little. These symptoms grow a little less intense with age, but the net effect of relaxation remains.

Yawning Cools the Body

According to the data that Gallup collected, in the initial stages of yawning, the stretching of the jaw facilitates the flow of blood to the neck, face, and head due to muscular contraction. Deep breathing squeezes blood and spinal fluid from the brain, probably the reason why we feel sleepy when we yawn. The cool air that comes from outside cools the fluids pulled down from the brain, decreasing the overall temperature of the body. Gallup conducted two studies in Tucson, one in winter, and one in summer. The results might surprise you:

Sure enough, in the cooler weather, 45% of people yawned when they looked at the pictures. But in hotter weather, only 24% of people yawned. Moreover, people yawned more if they’d been outside longer in the cool weather, and yawned less if they’d been outside longer in the hot weather.

The Emotional Aspect of Yawning

There are some people who are skeptical about the research on the cooling effects of yawning. The second most plausible theory about yawning is that it has no physiological effects, and is instead connected to the emotions of a person. However, we yawn in a variety of situations. We yawn when we are bored and are feeling lazy. We also yawn when we are exhausted.

There are so many triggers. People who sky-dive say they tend to yawn before jumping. Police officers say they yawn before they enter a difficult situation,” said Adrian Guggisberg, a professor of clinical neuroscience at the University of Geneva. Some scientists suggest that yawning might be important to sync the mental state of individuals and to subconsciously establish consensus about a situation i.e. the presence of danger.

Although both of these theories have their merits, there are still no surefire answers to why people yawn. Strangely enough, the concept of yawning is not only limited to humans. Almost all vertebrates yawn. Experiments have shown that chimpanzees sometimes yawn when they see humans yawn, thus it is apparent that the strange effects of yawning extend beyond the limits of species. What do you think about this strange aspect of human and animal psychology?





I am a History Educator and a Lifelong Learner with a Masters in Global History.