Maybe you stayed up college-era late at that soirée.

Or you woke up at 5 a.m. to make your flight to visit family. Don't panic. Judith Davidson, a sleep researcher and clinical psychologist at Queen's University in Kingston, Ont., says a night or two of staying up too late doesn't need to wreak havoc on your system.

Don't sleep in

Try not to sleep in for more than an hour past your usual wake-up time, says Davidson. This, along with sticking to your usual bedtime, will help your circadian sleep-wake rhythm remain stable. Resist the urge to go to bed early, which will make it more difficult to fall asleep and could start a pattern of poor sleep.

Take a nap

If your first impulse is to close your eyes, you're on to something. You needn't—and shouldn't—set aside much time for it, either. For most people (not including shift workers), a nap of under 60 minutes between the hours of 1 and 4 p.m. is enough to refresh you and won't mess up your bedtime, says Davidson.