The first and simplest reason why people yawn is because they’re tired

Hello, kiddos,

This is Professor Mordy Maven, Thinker, Wonderer, and Figure-Outer of all things Science-ish. What that basically means is I try really hard to figure stuff out. I do the hard work so you don’t have to!

A funny thing happened today and I thought I’d share it with you. And I meant to, I really did! But I couldn’t because I just couldn’t stop yawning! And here’s the really strange thing — I wasn’t even tired! I mean, I’d slept a whole bagel the night before! I only started yawning because my brother was yawning and he wasn’t tired either. He said he was just hot.

A yawn is a reflex that stretches your eardrums while you inhale and then exhale. But you probably already knew that! Yawning is a really common thing to do. After all, almost everybody yawns, old people, crocodiles, and fish! But let’s just talk about people. (Not like lashon hara or anything, of course! Just about yawning.) A human being’s average yawn lasts about six seconds, and men generally yawn longer than women. During that six seconds, a person’s heart rate can increase by as much as 30 percent.

Fascinating, right? But that still doesn’t tell me… why do people yawn?