Although lack of sleep is a proven fatigue trigger, research shows that disrupting your normal sleep cycle - by occasionally sleeping late or going to bed early - can sap your energy just as dramatically. These inconsistent sleep times can interfere with your body's ability to produce the sleep hormone melatonin, making the sleep you do get less restorative.
To fight fatigue, it's best to try to keep your bedtime and wake-up time as consistent as possible. Yup, even on weekends! If your body is still craving for that extra shut-eye, opt for a 2- to 40 minute afternoon nap instead of extending your nighttime rest. Studies show that people who erase sleep debt with naps have better nighttime melatonin production, plus they feel more energetic than those who turn in earlier or hit the snooze button in the morning.