Why Do I Yawn, and Do People Yawn When They’re Bored? Experts Explain

Humans’ first experience with yawning happens in utero, says Matthew D. Epstein, M.D., associate medical director of the Atlantic Health Sleep Centers in New Jersey. Yet, Earth-side, the somewhat-involuntary action can be perceived as a sign of boredom—think: during a monotoned lecture, a long road trip, or while watching TV. In reality, yawning’s triggers are much more layered than that. So, if you’re chatting with someone who reaches to cover their mouth, try not to be offended right away.

Below, experts explain what a yawn is, what causes one, and they delve into theories that connect yawning and boredom.

Yawning is an innate and reflexive behavior characterized by an ajar mouth accompanied by a deep inhalation and stretching of muscles around the throat, explains Epstein. That’s followed by a a brief pause, a rapid release of the muscle tension, and an exhalation. Yawning is also phylogenetically preserved, meaning it occurs in many different animal species including mammals, birds, reptiles, amphibians, and fish, Epstein adds.

Karen D. Sullivan, Ph.D., board-certified neuropsychologist and creator of I Care For Your Brain calls boredom-induced yawning the “biggest myth” associated with the action. That’s because yawning is, more specifically, associated with “any low-vigilance state in the brain,” she says. “The boredom connection is really more of a sleepiness connection, or when we’re just kind of not engaged with something in our environment and the brain is kind of transitioning towards sleep.”

Studies have found that yawning boosts arousal and promotes circulation. “In the five seconds it takes to yawn, you’re not only seeing an increase in oxygen, but all of the things that contribute to increased circulation,” explains Sullivan, such as a spiked heart rate and increased skin conductance.

Yawning has also been likened to “a hit of caffeine,” Sullivan adds. “So anytime that we’re kind of threatened by being under-stimulated or overstimulated, that [yawning] part of the brain kicks in,” she explains.

There’s also a social-evolutional aspect to it: in animals, yawning, particularly while showing teeth, is a power move that shows dominance or intimidation. That might explain why, in humans, yawning without covering your mouth is socially foreseen as a sign of boredom or disrespect, Sullivan adds. “It’s definitely a very strong interpersonal communication,” she says.

It was once believed that the main function of yawning was to increase otherwise low oxygen levels, but a 1987 study disproved that theory. And despite extensive additional research on yawning, its true purpose remains uncertain, says Epstein. However, there are a few other biological factors researchers think contribute, including:

Brain temperature regulation

Yawning facilitates cooling of the brain, explains Epstein. This happens via blood flow, the inhalation of cool air, and the occasional tearing of the eyes. It has also been found that yawning occurs before, during, and after instances of abnormal thermoregulation, like heat stress and hyperthermia. This explains why people with medical conditions that cause an increased core body temperature like multiple sclerosis (MS), epilepsy, anxiety, and head trauma experience excessive yawning followed by temporary relief from symptoms.

Improved respiratory function

“The airway is never more wide as during the five second peak of a yawn,” says Sullivan. And a recent hypothesis, Epstein adds, suggests that those stretches and repositions of the upper-airway muscles may acutely improve respiratory function.

Social empathy

As you probably know, yawning is contagious—you might be resisting one now. That’s thanks to the brain’s mirror neuron system, explains Sullivan, which is thought to be an evolutionary phenomenon linked to our ability to imitate, empathize, and participate in group behaviors. “It goes back to kind of pre-language, before we were able to speak,” she says. “This is how we really developed as a species, through social learning.”

Excessive yawning is usually no cause for concern and likely just indicates drowsiness. However, in some cases, extra yawns can flag something more serious, like a vasovagal syncope (a sudden drop in blood pressure and heart rate that leads to fainting), neurological conditions like epilepsy and MS, or in rare cases, a brain tumor.

Yawning often feels involuntary—it’s triggered by the same part of the brain as sneezing, Sullivan says. But the difference is, a yawn can be controlled from “the top down” if you think about it hard enough, she adds. So if you feel one coming on during a one-on-one with your boss, not all hope is lost. “You can stifle it,” Sullivan says. “I think that’s because yawning has this more social component, which is very interesting.”

Kayla Blanton

Kayla Blanton is a freelance writer-editor who covers health, nutrition, and lifestyle topics for various publications including Prevention, Everyday Health, SELF, People, and more. She’s always open to conversations about fueling up with flavorful dishes, busting beauty standards, and finding new, gentle ways to care for our bodies. She earned a bachelor’s degree in journalism from Ohio University with specializations in women, gender, and sexuality studies and public health, and is a born-and-raised midwesterner living in Cincinnati, Ohio with her husband and two spoiled kitties.