Jan. 14, 2002 -- How much sleep do you really need? No standard answer exists. Generally, researchers agree that "optimal" sleep is the amount that leaves you feeling awake and alert all day long. Most people need a full eight hours; some do well on six.
In Power Sleep (HarperCollins, for about $13), Cornell University psychologist James Maas suggests a "sleep quotient" experiment: For one week, go to sleep a full eight hours before you need to get up. If you rise rested and ready to go -- and feel that way throughout the day -- you've gotten enough sleep. If not, try changing your bedtime by adding to it (or subtracting from it, if necessary) by 15 to 30 minutes for a week. Eventually, you should discover the amount of sleep that works for you.
Alternatively, you might try keeping a sleep diary. Record the time you sleep and how you feel the next day to find the best sleep pattern. When your snooze schedule reaches perfection, you'll wake up in the morning at the right time, even without an alarm clock.
Your sleep style is partly genetic. Several "clock" genes influence our natural sleep/wake cycles, or circadian rhythms. At night, when it's time to rest, these genes start winding your body down, increasing drowsiness, for example, and lowering your temperature and heart rate. Last fall, Emmanuel Mignot and colleagues at Stanford University found telltale differences in one clock gene among people who were night owls and those who were morning larks. Tuning into your natural rhythms may be the secret to blissful sleep -- and busy days.
It worked for Carol Ezzell, an editor in New York. Never one to embrace the dawn, Ezzell has designed a work schedule around her creative highs. She arrives at the office around 10:30 a.m and stays until 6:30 at night. "I'd rather eat a quick lunch and work late than fight to be productive early in the day," Ezzell says. "I just don't do good work in the early morning."
It doesn't really matter when you go to sleep or wake up, researchers say, as long as you're consistent. Nod off around 10:30 every night, and you'll snooze more quickly and feel alert the next day. Bounce bedtimes around, however, and you're more likely to feel grumpy and drowsy. Sleeping in on Saturday morning also can short-circuit your sleep cycle by making it difficult to fall asleep that night. Then Sunday becomes a bear. As Maas puts it, "You cannot make up for large sleep losses during the week by sleeping in on weekends any more than you can make up for lack of regular exercise and overeating during the week by working out and dieting only on the weekends."