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Be a Clock-Watcher

Irregular Work Schedules and Sleep (1:25)

Lawrence J. Epstein, MD, of Harvard, explains why people who work irregular hours often have trouble with sleep.

Learn to tell time on your body clock. Then use body time to organize your day. 

People with regular wake up times and bedtimes usually know the approximate time they will start to feel drowsy. People with irregular work and sleep hours have to work harder to recognize sleepiness clues. Watching your body clock can help.

The hours you have been awake play a critical role in controlling your alertness and sleepiness over the day. Make a habit of tracking the number of hours you have been awake. When did you wake up today? How long have you been awake now? Find out about your own body’s sleep drive, and check your sleep debt.

Learn to tune in to your body's warning signals. After you stay awake for 12 hours or less—especially if you did not sleep enough in your last main sleep period—ask yourself: Is my mind wandering? Am I yawning? Do I feel chilly? Am I nodding off? 

These clues mean you need to ramp up efforts to stay alert: Get up and stretch, move around, and talk with co-workers. Take a nap if you can—no more than twenty to thirty minutes—or consume caffeine, if the time is right. These tactics may boost alertness temporarily, but they are not a substitute for adequate sleep. Aim to make up lost sleep as soon as you can.  

After being awake for 15 to 16 hours, everyone needs sleep. If you must stay awake beyond that range, remember that your alertness likely will be down. Take steps necessary to assure your safety. Go to sleep as soon as you can.