Unless the yawning is excessive and doesn’t show signs of stopping, it’s totally normal. Yawning helps us make transitions in our physiological and behavioral states, such as from sleep to wakefulness or from sedentary to active, says Robert R. Provine, PhD, a neuroscientist and professor of psychology at the University of Maryland, Baltimore County, and author of Curious Behavior: Yawning, Laughing, Hiccupping, and Beyond. When you yawn during activity, he says, it stirs up certain body functions, which affect your blood pressure, heart rate, and body temperature. It’s also associated with anxiety (like at the start of an event), but it typically fades away. If it doesn’t, there may be more to your yawning than simply waking up or being nervous. Certain medications, particularly antidepressants, can trigger excessive yawning. Another…