People do it. Dogs and cats do it. Even snakes and frogs do it. We all yawn – even in the womb.
Even the word “yawn” can make a person yawn.
Pictures of animals and babies yawning, will make you yawn. You’re probably yawning just reading this.
But even though we all do it, science still doesn’t completely understand why we do it (kind of like the mystery of sleep). Instead, we have a handful of theories, some correlations, and we know, with 100% certainty, that yawning is contagious: talking or writing about it and seeing or hearing it can make you yawn (it’s called an echophenomena).
So why do we yawn?
The truth is, we don’t really know.
What we do know, is that a primal centre of our brain triggers yawning and that it’s outside of our control – we do it subconsciously. Even when we’re paralyzed or have lost intentional control of our bodies, we can still yawn. Darwin noticed it in 1838 and neuroscientist, Robert Provine notes that we’re just “playing out a biological program” kind of like laughing and hiccuping – it just happens, spontaneously and unintentionally, and we can’t stop it once it starts.
Here are the top yawning theories:
You’ve probably heard someone say that yawning is your body’s attempt to get more oxygen or rid itself of built up carbon dioxide. Theorists associate it with sleepiness by stating that increased oxygen helps wake us up – it’s a common theory, but we know it’s wrong because if we need to yawn to get more oxygen, we’d be doing it when we’re exercising.
Robert Provine tested this theory by giving people extra oxygen in addition to decreasing carbon dioxide, and neither prevented yawning and Steven Platek, a psychology professor, also tested to see if yawning affected oxygen levels in the bloodstream, blood pressure, and heart rate and it proved nothing.
This theory posits that yawning is the body’s radiator – it cools the brain. Psychologist Andrew Gallup tested this theory by applying hot and cold packs to the forehead to see if it impacted yawning.
Results showed that the warmer the forehead, the more people yawn, the cooler the forehead, the less we yawn. This theory is also supported by the fact that our brain and body temperatures are the highest before we fall asleep.
The theory of thermoregulation ties yawning substantially to sleep – although yawning has always been known to indicate tiredness or sleepiness.
Without a doubt, tiredness elicits yawning (though boredom doesn’t, contrary to widespread belief). But why yawning grows more intense the sleepier we feel, it’s not related to how much sleep we get.
However, persistent sleepiness and daytime drowsiness can be a symptom of a common sleep disorder: sleep apnea.
Others theorize that yawning is a form of communication – that we yawn as a way to demonstrate empathy. One study illustrates that we’re more likely to yawn in response to people we know yawning than strangers yawning (which supports the idea that we can empathize better with those we know).
Interestingly, other studies indicate that people with schizophrenia and autism (conditions that hinder empathy) are less likely to yawn in response to someone else yawning.
Can Yawning Be Excessive?
Yes. While yawning is involuntary and a natural response to tiredness, it can be excessive. When it is, it’s usually a symptom of an underlying medical condition. At worst, ongoing, excessive yawning can be a symptom of a stroke, multiple sclerosis, epilepsy, or heart attack.
While sleep apnea can be dangerous if left untreated (think high blood pressure, stroke, obesity, diabetes, heart disease, depression, anxiety, accidents), sleep apnea treatments can mitigate these dangers and combat your excessive yawning. Think you might have it, take our sleep quiz to find out how high your risk is.