Why Do We Yawn? 4 Reasons, According to Science

Yawning is a reflex action in which you open your mouth wide and take in a deep breath before exhaling. It has various causes, including sleepiness, boredom, regulating brain temperature, and relieving ear pressure. Yawning is also contagious as seeing someone else yawn often triggers us to yawn too, possibly due to an empathy response. Sometimes, excessive yawning can be a sign of a health issue, such as narcolepsy, sleep apnea, stroke, or anxiety. While most people yawn five to 10 times a day, some people might yawn up to 100 times in a 24-hour period. It's recommended to see a doctor if excessive yawning is coupled with other symptoms.

Yawning is a universal human experience. And it doesn’t stop with us. Animals yawn too—from your house cat stretching in the sun, all the way up to African and Asian elephants.

Most people think yawning happens because you’re sleepy. That’s true. But it’s not the only reason why you might yawn. There’s much more to yawning than meets the eye—and while this action is a normal human function, it can sometimes be a sign of a more concerning issue, like narcolepsy or sleep apnea.

Learn more about why we yawn, why we yawn when we see someone else yawn, and how much yawning is too much.

What is yawning?

You probably already know what yawning is, but here’s a quick definition: Yawning is a reflex where your mouth opens wide; you take in a long, deep breath (your eyes might close or your head might tilt back); and then exhale as you close your mouth.

It’s involuntary, which means that if you feel a yawn coming on, it’s difficult to suppress. Human yawns can last anywhere from four to 10 seconds.

Why do we yawn?

There are several reasons why we might yawn. These include sleepiness, boredom, and regulating brain temperature. The four most common causes of yawning include:


You likely notice yourself yawning the most when you’re sleepy or drowsy—maybe when you’ve just woken up in the morning or when it’s almost time for bed at night. Yawning can help your body stay awake (while also signaling to you that it would appreciate some sleep).


Boredom and a lack of stimulation can make you yawn. Again, your body is trying to wake itself up, keeping you alert if you’re struggling to focus on a long class or a boring movie.


Yawning can actually help regulate your brain temperature. Inhaling air can help your brain cool down if it gets too warm—no wonder people yawn more during the summer.

Ear pressure

One final reason why you might yawn is to change your ear pressure. Yawning can relieve pressure in your ears if you’re flying on an airplane or driving through the mountains, sometimes making your ears “pop.”

Why do we yawn when we see someone else yawn?

Have you been yawning throughout this entire article so far? If your answer is yes, that’s not surprising. Seeing somebody else yawn or even reading the word often triggers us to yawn too.

Scientists think this might be an empathy response. You might be experiencing echopraxia—where you automatically mimic someone else’s movements. Or we may feel prompted to yawn in a group setting as a way to keep us all alert.

It’s worth considering too, that if you see someone yawn in the same room as you, you’re both being exposed to the same environment and the same temperature. So you may simply be simultaneously reacting to what’s around you, both noticing that you’re tired at the same time.

Why do we cry when we yawn?

You might notice that sometimes, you tear up when you yawn. This is completely normal to experience. The action of yawning pulls on the lacrimal glands, which are located above your eyeballs and produce tears.

This pressure can stimulate the glands and make tears come out. Your eyes also might be dry and fatigued, which can cause tear production too.

How much yawning is too much?

According to experts, there’s no definitive answer on how much yawning is too much. While most of us yawn around five to 10 times a day, everyone is different, and some people might yawn up to 100 times in a 24-hour period.

However, it’s helpful to realize that excessive yawning like this could be a sign of a larger health issue—something deeper than just skipping your coffee this morning. Yawning frequently during the day could be a side effect of medication or a sign of health conditions such as:

If you’ve been dealing with yawning that just won’t stop—especially if the yawning is coupled with other symptoms like drowsiness or breathing problems—make an appointment with your doctor to get to the root of the problem.


What is the real reason for yawning?

You might yawn because you’re sleepy, you’re bored, or your brain is overheating.

Do we yawn because we need oxygen?

Most likely, no. Experts used to think this was the case, and it’s true that a yawn could help more oxygen get into your body. But more recent research has shown that we likely yawn for other reasons instead.

Why is yawning so contagious?

Scientists think yawning may be contagious because we feel empathetic, leading us to automatically imitate what someone else is doing.

Do you feel tired all day long? Learn more about excessive daytime sleepiness and how to treat it.

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