By the way, doctor: Why do I yawn when I exercise?
Q. I'm 40, and for the past few years I've been starting to yawn whenever I get an intense aerobic workout. Is this something I should worry about?
A. We usually think of yawning as a sign of sleepiness or boredom, but experts say that isn't the whole story. True, we tend to yawn toward bedtime as we get sleepy, but we also yawn in the morning when we wake up. Athletes yawn before they compete — not a time associated with boredom or sleepiness. And we yawn in response to seeing someone else yawn, even if we're not sleepy or bored.