DOZIN' ON SUNDAY AFTERNOON
- 10 minutes -- A quick fix. napping for 10 minutes immediately wards off fatigue and boosts brain power for at least 2 and a half hours, an Australian study found. A 5 minute nap is no help.
- 20 minutes -- Delayed benefits. Doubling down will improve your reaction time and performance on alphanumeric task. But not right away it takes at least 35 minutes to shake off the postnap mental fog from "taking 20."
- 30 minutes -- A healthy boost. You will feel drowsy for about 5 minutes afterward, but then more mentally fit for 90 minutes. Still, a 10 minute nap is better; you avoid the hangover effect of a deeper sleep.
- 45 to 90 minutes -- No help. During a 45 minute to 90 minute nap, you drift into deep sleep without completing a full sleep cycle. "You will often feel worse after you wake up than before," says sleep expert W. Christopher Winter, M.D.
- 90 to 110 minutes -- Sings of trouble. The average person's sleep cycle last 90 minutes, the ideal duration for a longer snooze. But habitual long napping may be a sign of a sleep disorder, Dr. Winter says.