There is more to yawning

By Maya Totev •

Going to sleep, waking up in the morning, attending a meeting, or sitting in a two-hour long lecture can all have one thing in common: a deep inhalation of air, a phenomenon we call yawning.

“I never really thought about how yawning interacts with the rest of your body. It seems like something that just occurs,” said Madeline Hsu, freshman psychology major.

Omar Eldakar, biology professor at NSU, and a former colleague, Andrew Gallup, researched the real reason for yawning and its effects on the brain.

One of the most common misconceptions is that yawning occurs to increase oxygen levels in the brain, but Eldakar said that it is not triggered by the excess or lack of oxygen.

“We yawn spontaneously to cool the brain. You inhale air and that cools the blood around your lungs,” Eldakar said.

Eldakar said heart rate and blood pressure increase with yawning, and the flexing of the jaw muscles helps push the warm blood out of the areas. Cooler blood is introduced and helps reduce the temperature of the brain.

Jack Walsh, freshman biology major, said he never knew why people yawn and the purpose it serves.

“It turns out yawning is kind of like an air conditioner system in which yawning is doing the cooling for our bodies,” Walsh said.

Factors that increase brain temperature and cause people to yawn include exercise, external temperature, stress, anxiety, drugs like SSRIs (selective serotonin reuptake inhibitors), drug withdrawals and certain diseases.

“The problem is that the brain is such a big metabolic energy user, so it can just simply run hot,” said Eldakar.

Several NSU students attribute yawning to being tired or bored, based on personal experiences.

“I yawn most in the morning and at night before bed. Last year, I would yawn so hard every single time I specifically went to English class,” said Walsh.

But Eldakar noted that yawning occurs mostly during certain times of the day due to bodily temperatures, not tiredness.

“Before you go to sleep or when you wake up, you experience a lot of yawning. This is because your body temperature is the greatest at both of these times,” said Eldakar. “When brain temperatures are elevated, you fall asleep, and yawning is a method to counteract those effects.”

Yawning is further constrained to an optimal thermal zone depending on the temperature outside.

“If it is cold outside, yawning can cool your brain too much. If it is hotter than your body temperature outside, yawning will heat your brain further,” said Eldakar. “Too hot or too cold of temperatures are outside of the thermal window, so yawning should be diminished. Within that range is the thermal neutral zone, where we expect yawning to occur.”

If a picture or video of someone yawning, known as a contagion stimulant, is presented to an individual who is in very hot or cold temperatures, the contagion stimulant will not act upon them.

“If an individual is freezing, the contagion effect is telling the person to yawn, but the thermoregulatory aspect is telling the person to not do it because the air is too cold. They are counteracting each other,” said Eldakar, who is also interested in the relationship between stress and yawning, and whether stress is suppressed or accentuated.

“When individuals get an increase in bodily temperature that accompanies stress, you want to preserve it since it means the body’s awareness is heightened. When the stress is officially gone, you want to spill off that extra heat,” said Eldakar. “This was seen when the test subjects had elevated body temperatures as a response to stress until they began yawning like crazy after 20 minutes.”

Psychopathy and contagious yawning also have a relationship.

“We conducted the largest study ever on contagious yawning and measured psychopathy traits in people. Individuals that scored higher on the psychopathy scale were less likely to yawn contagiously,” said Eldakar.

Students can learn more about topics like yawning and how it works in a course that NSU offers, taught by professors including Eldakar.

Thomas Steckman, freshman business marketing major, previously took the class.

“I took a course called the Study of Darwinism and we did a couple of chapters regarding humans, part of which included yawning,” said Steckman, who found it interesting to learn about important concepts regarding humans.