Here's The Real Reason Why You Yawn

The human body can do some strange and involuntary things, from sneezing and burping to farting. What threads these responses together, however, are actions that lead to a reaction. A sneeze can be brought on by all manner of things, as can a burp or a fart. But with a reflex such as yawning, it's a little more mysterious.

More often than not, you'll catch yourself yawning in particular situations — either you're feeling extra tired or incredibly bored. But the reason why we yawn is a lot more complex than that. For a long time, it was believed that yawning was a sign that your body was in need of more oxygen. But, as Healthline notes, this is no longer the case.

In 2014, research published in the Physiology & Behavior journal (via Science Direct) found that the involuntary reflex of yawning has more to do with regulating temperature in the brain than providing your lungs with more oxygen.

You're more likely to yawn during a particular season of the year

As researchers from the University of Vienna found (via the Independent), yawning actually helps the body regulate its temperature. Similar to how sweat cools the outside of the body, a sharp intake of air — accompanied by increased heart rate and blood flow – can cool the brain down in an instant.

Per the study (via Science Direct), this all depends on the temperature of the air. Researchers tested the effects that summer and winter conditions would have on its participants, with more experiencing moments of yawning in hotter temperatures than those in cooler ones. As concluded by the evidence, the study put forward the notion that yawning has everything to do with thermoregulation rather than oxygen deprivation.

As for why you yawn when you're tired, this is because your brain struggles to maintain a constant temperature according to Boston University's The Nerve Blog. So to keep your thermoregulation at its optimum setting, the brain uses the yawn reflex to cool down.

Contagious yawning occurs because of a totally different reason

But what about contagious yawning? Well, that's a little more complicated. While the actual reason as to why humans that see others yawning feel the need to do it themselves is still up for debate (via Science Daily), it seems to be related to emotions rather than thermoregulation. According to a 2015 study published in the Personality and Individual Differences journal (via Science Direct), researchers at Baylor University discovered that the more amount of empathy you had for others increased the chance that you'd contagiously yawn.

Another study conducted by the Universities of Turin and Pisa in 2020 (via Frontiers in Psychology) found that the higher a bond you have with someone, the more likely you are to "catch" a yawn. Researchers also found that when providing just the auditory sound of a yawn, it was "significantly more frequent between kin and friends than between strangers and acquaintances," as noted in the study.