Why do we yawn?
Everyone yawns, including adults, babies, and even animals. Scientists don't know exactly what causes yawning. But he has a few theories on the subject...
Most people associate yawning with being tired or bored. Studies of other mammals, such as sea lions, have also shown that they yawn more often when resting or sleepy. Recent research suggests that yawning may serve important physiological or social functions beyond simply showing that we are tired.
Why do we yawn?
Scientists have yet to reach a consensus on why we yawn. Some scientists claim that yawning serves a physiological function, such as helping the brain wake up or cool down. Others argue that yawning serves a psychosocial function by enabling people to communicate that they are sleepy, bored, or stressed.
Theory 1: Yawning awakens the brain in times of boredom or fatigue.
One theory argues that yawning can help keep the brain alert during boring or passive activities. The action of yawning forces the muscles of the face and neck to move. Researchers believe this action can stimulate the carotid artery, leading to an increase in heart rate and the release of hormones that promote alertness. Experts theorize that yawning can directly affect brain activity by causing brain fluid to move away from its resting network and into a more active state. The electrical conductivity of the skin also increases during yawning, similar to the effects of caffeine. Because caffeine promotes alertness, the researchers speculate that similar physiological response may indicate that both serve the same function.
To add further evidence to this theory are the types of activities where yawning is more likely to occur. For example; People are more likely to yawn when they are engaged in a more passive activity, such as driving, watching TV, or listening to a lecture. They're less likely to yawn when they're doing something more active, like cooking or talking.
Theory 2: Yawning helps cool the brain.
Yawning may aid in brain thermoregulation, or the process of maintaining the brain's core temperature. During yawning, the facial muscles move and contract, increasing blood flow to the face where heat can dissipate more easily. Some people's eyes water when they yawn, which can release heat. Likewise, a deep breath of fresh air can help send cooler blood to the brain.
Although more research is needed, preliminary studies in humans and animals have provided evidence for the thermoregulation theory. For example; A study of budgies found that they yawn more when the ambient temperature rises, especially as they approach their body temperature. In a human study, researchers placed a hot pack and an ice pack on participants' foreheads while watching videos of people yawning. In response to the videos, those who kept warm yawned more, while those with ice packs yawned less.
Studies on seasonal changes in ambient temperature also provide support for the thermoregulation theory of yawning. For example; One study asked participants to self-report how many times they yawned during the winter and summer months. The researchers found that participants were significantly more likely to report yawning during the hotter summer months. This correlation persisted after other variables such as humidity or sleep were taken into account.
People with certain conditions that increase their core body temperature, such as multiple sclerosis, anxiety, or a stroke, may find that yawning temporarily relieves their symptoms. These conditions often cause excessive yawning, which can be a natural response to overheating.
Theory 3: Contagious yawning is linked to empathy skills.
The contagiousness of yawning suggests it may be an empathetic response that helps humans and other mammals communicate. Brain imaging reveals that when a person watches someone yawn, they show an increase in the activity of parts of the brain associated with empathy and social behavior.
Studies show that the closer a person feels to another person, the more likely they are to yawn when that person yawns. In other words, a person is more likely to yawn after seeing a friend or family member yawn than an acquaintance or stranger. While people yawn as infants, they do not become susceptible to contagious yawning until around age 4 to 5, when they develop the mental ways to understand how other people are feeling.
According to some research, contagious yawning is associated with higher empathy. Conversely, disorders that impede social skills, such as schizophrenia or autism spectrum disorder, also appear to reduce contagious yawning. People who score higher on selfishness, callousness, and other antisocial personality traits are less likely to yawn in response to others' yawns, but fatigue still seems to play a larger role.
Other theories about why we yawn
Yawning helps open your Eustachian tubes that connect your throat to your ear. This action can help relieve the uncomfortable pressure build-up in the ear, for example when landing an airplane. However, since swallowing achieves the same purpose, scientists do not believe it is the primary reason we yawn.
What causes excessive yawning?
There is no official consensus on how much yawning is too much, but some experts consider it abnormal to yawn more than three times in a 15-minute period unless there is an obvious reason. The average person yawns up to 28 times a day, usually after waking up and before going to bed. Yawning in the absence of fatigue, boredom, or other typical symptoms is also considered abnormal and may indicate an underlying disorder.
Excessive yawning can result from damage to the parts of the brain involved in yawning. Too much yawning can be a sign of conditions such as:
- Paralysis
- Parkinson's disease
- Epilepsy
- Migraine
- multiple sclerosis
- Brain tumor or swelling
In rare cases, certain medications such as antidepressants, opioids, dopaminergic drugs, and benzodiazepines can also cause yawning. People with sleep disorders such as insomnia or obstructive sleep apnea (OSA) are also more likely to experience excessive yawning.
When should you talk to your doctor about yawning?
Yawning is common after seeing someone else yawn, or when you feel tired, bored, hungry or stressed. If you are yawning more than usual and you are not sure why, be sure to consult a doctor. You should also consult your doctor if you are yawning a lot due to insufficient sleep or if you feel sleepy during the day.
