Yawning is one of the most common but least understood human behaviors. Although virtually every animal with a backbone yawns, science still has many questions about yawning that don’t have definitive answers. These include the question of whether a person can yawn in their sleep.
So far, there haven’t been any scientific studies dedicated to answering this question. But small babies have been observed yawning in their sleep. And in one study, an adult participant reported having fits of yawning that could wake them up from a sound sleep. However, for both babies and adults, yawning while sleeping is believed to be very rare.
Scientists are still conducting research to discover the function behind yawning. Many theories have emerged, from social communication to temperature regulation. We review these theories, as well as what’s known about when and how we yawn.
What Is a Yawn?
A yawn is an action involving coordinated movement of the muscles and organs in the chest, throat, and mouth. A person yawning opens their mouth wide, extends their jaw as far as possible, inhales deeply at length, then exhales slowly. While they yawn, they may also stretch their arms or legs.
People typically yawn up to 28 times a day, with each yawn lasting for 5 to 10 seconds. Their yawns are involuntary, or at best semi-voluntary. People can’t yawn at will or when they are told to do so. And it can be difficult or impossible to suppress a yawn once it begins.
Studies suggest that many kinds of brain activity and chemicals are involved in yawning. Some scientists believe yawning may be linked to the body’s circadian rhythms, biological patterns that direct different functions like sleep and body temperature.
When Do People Yawn?
People often yawn during transitions between wakefulness and sleep. Yawning can be part of a person’s waking ritual or a signal that lets people know when bedtime is near. People also yawn in response to stress, overwork, tiredness, lack of stimulation, hunger, and fullness.
Although people yawn at all ages — even before they are born — the time when people yawn the most appears to shift and change with age. Adults tend to yawn late in the evening and early in the morning. But according to one study, young children are most likely to yawn after waking up from their morning and afternoon naps.
The season and the temperature outside can also affect how often people yawn. The amount of times a person yawns is connected to seasonal variations in climate. Yawning is associated with cooler temperatures, but is less frequent during summer-like conditions of high temperature and low humidity.
Why Do People Yawn?
Research suggests that sleep deprivation and feeling drowsy commonly cause people to yawn. But scientists do not yet fully understand all the underlying reasons why people yawn or the functions that yawning serves. Still, experts believe that yawning has both a social and a biological function.
One theory for why people yawn is that yawning is an empathetic communication tool. This means that it helps people alert others to their unpleasant feelings and states of mind. Other possible reasons involve changes in the body and unconscious imitation of other peoples’ behavior.
- Boredom: Yawning is associated with uninteresting and repetitive things and can be a sign that a person is bored.
- Contagiousness: People can be prompted to yawn if they see, hear, read, or think about yawning. One study found that 42% to 55% of people will yawn during or after watching a video of someone yawning.
- Brain temperature: One theory suggests that yawning helps to regulate brain temperature and that it may help with cooling the brain when its temperature increases.
- Ear pressure: Yawning can relieve the unpleasant ear pressure that builds up during plane flights, elevator rides, and other situations that lead to air getting stuck in the ear. The contraction and relaxation of muscles involved in yawning can help adjust the air pressure in the ear.
- Substances: In rare cases, yawning can be a side effect of certain medications like opioids and antidepressants. Yawning may also occur after withdrawal from long-term use of opioids or coffee.
When to See a Doctor
You may want to reach out to a doctor if you find yourself yawning compulsively or more often that is normal for you. This is especially true if you get enough sleep but still yawn frequently, even when you don’t feel fatigued, bored, or tired.
There is no official guideline on what is considered abnormal yawning. However, some experts consider yawning three or more times in 15 minutes to be excessive.
Excessive yawning can be associated with sleep disorders such as insomnia and sleep apnea. But other disorders and health conditions can also make you yawn too much. Your doctor can evaluate you and review your medical history to help determine what is causing you to yawn and what treatment might be best for you.
References
About The Author
Staff Writer, Sleep Health
Afy is a writer and creative strategist in San Francisco with a master’s degree in international health policy from the London School of Economics. She has written for VeryWell Health, BlackDoctor.org, and Paste magazine and edited peer-reviewed journal manuscripts for Elsevier. Afy says her work with The Sleep Doctor is anything but “sleepy.” She enjoys the opportunity to learn new information and share knowledge that gives people the power to make better choices. Afy also likes to read non-fiction, do creative writing, and travel solo.
- POSITION: Side sleeper
- TEMPERATURE: Hot Sleeper
- CHRONOTYPE: Bear
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