It's Monday, so if you've been yawning all morning, you're not alone.    But do you know WHY we yawn?  It seems like something we'd have an answer for by now, but we don't. But, I scoured the internet so you won't have to, and found out some stuff.  Here are the three leading theories, and why they're STILL theories.

Theory #1.)  It Makes You More Alert.  It makes sense, because you get a big gulp of air, plus you open your mouth wide and stretch your whole face out.  But researchers monitored people's brain activity while they were yawning, and it didn't seem to increase the type of brainwaves associated with being more alert.

Theory #2.)  You Need More Oxygen.  It does force you to take a deep breath.  But you actually take in more oxygen by breathing a little FASTER than you do by yawning.  So if our bodies make us yawn just to get more oxygen, it's kind of a weird way to do it.

Plus, most people don't yawn more when they exercise, which is when you DO need more oxygen.

Theory #3.)  It Gets the Stale Air Out of Your Lungs.  Most of the air in your lungs is replaced every time you take a breath.  But not all of it.  When you breathe out, a little bit of air stays in your lungs because it HAS to.  If it didn't, they'd collapse.

So the theory is basically that "stale" air . . . which means air that's low in oxygen . . . builds up all the time.  And yawning is your body's way of making sure it gets replaced every so often.  But this one has the same problem as #2, which is that yawning doesn't actually increase the amount of oxygen you take in.  At least not by much.  Which is why this one might just be something that SOUNDS right.

What do you think? Do you feel like you yawn a lot?

Yawnily yours,