Nobody really knows for sure why we yawn, let alone why some people yawn excessively at the beginning of a workout. Researchers used to speculate that yawning helps increase oxygen flow to your brain. However, a University of Maryland study found that there’s no relation between yawning and breathing, largely discrediting this theory. Instead, yawning may be your body’s way of dealing with transitions, such as when you’re waking up, getting bored, or working out. “If you jump straight into a workout, your body is still adjusting to your change in breathing and blood vessel dilation. Yawning may be an indicator that you’re warming up,” says Alice Burron, MS, exercise physiologist and spokesperson for the American Council on Exercise.
Fix it: A little yawning at the start of exercise is nothing to worry about. However, excessive yawning could be a sign of an underlying heart and blood pressure issue and should be checked out by a doctor.