What makes us yawn?

Life is filled with little mysteries, one of which is why we’re more likely to yawn when others around us.

However, new research from the University of Vienna suggests that group yawning is actually a survival mechanism that has the side effect of cooling off our brains, which in turn makes us more alert and less likely to doze off.

In other words, the scientists discovered that people were less likely to yawn contagiously in either very hot or very cold temperatures because in those temperatures yawning would have very little impact on the brains temperature.

In fact, the researchers pointed out that yawning excessively in the cold might even have “harmful consequences” because it might make the brain too cold.

So what's behind this mysterious epidemic of yawning? First, let's look at what this bodily motion is: Yawning is an involuntary action that causes us to open our mouths wide and breathe in deeply. We know it's involuntary because we do it even before we're born.

According to research, a developmental neuroscience at the University of Maryland, Baltimore County, research has shown that 11-week-old fetuses yawn. And while yawning is commonly associated with relaxation and drowsiness, your heart rate can rise as much as 30 percent during a yawn, and yawning is a sign of arousal, including sexual arousal.

Many parts of the body are in action when you yawn. First, your mouth opens, and your jaw drops, allowing as much air as possible to be taken in. When you inhale, the air taken in is filling your lungs. Your abdominal muscles flex, and your diaphragm is pushed down.

The air you breathe in expands the lungs to capacity and then some of the air is blown back out. And, sure enough, that’s what they observed:

People yawned more when the temperature was around 20°C (68°F) — this included contagious yawning, where one person sets off other people’s yawns.

People yawned less when the temperature dropped towards freezing and less when it soared up to 37°C (98°F) in the Arizona summer.

Yawning, then, is highly beneficial in that it can help bring the brain back into the correct temperature range.

When the brain is at the right temperature, it operates more efficiently, helping us to think faster.