January 4, 2000

Science Times
New Respect for the Nap, a Pause That Refreshes
By JANE E. BRODY

You must sleep sometime between lunch and dinner, and no halfway measures. Take off your clothes and get into bed. That's what I always do. Don't think you will be doing less work because you sleep during the day. That's a foolish notion held by people who have no imaginations. You will be able to accomplish more. You get two days in one -- well, at least one and a half."

--Winston Churchill

As a short sleeper who is rarely in bed for more than six hours a night, I'm a strong believer in naps for recharging my batteries. Sir Winston and I are in good company. Napping enthusiasts have included Albert Einstein, Napoleon Bonaparte, Thomas Edison and at least three presidents: John F. Kennedy, Ronald Reagan and Bill Clinton. Besides, sleep researchers have shown that regardless of how long one sleeps at night, the human body is programmed to become sleepy in the early afternoon, even without a big lunch.

 
Losing Sleep
This is the second of two columns on sleep debt. Last week: cheating on sleep.

 

"Napping should not be frowned upon at the office or make you feel guilty at home," writes Dr. James B. Maas, a psychologist and sleep expert at Cornell. "It should have the status of daily exercise."

In the old days, people would doze for an hour or so after the midday meal, and in some Latin American and European countries siestas are still in vogue. But in most industrialized nations, the usual response to the afternoon sag in energy is to try to jump-start the system with caffeine, a tactic that sleep experts say is actually counterproductive, creating only the illusion of efficiency and alertness and depriving the body and brain of much-needed sleep.

How Naps Help

Now, however, there is growing evidence that restorative naps are making a comeback. Recognizing that most of their employees are chronically sleep-deprived, some companies have set up nap rooms with reclining chairs, blankets and alarm clocks. If unions are truly interested in worker welfare, they should make such accommodations a standard item in contract negotiations.

Workers who take advantage of the opportunity to sleep for 20 minutes or so during the workday report that they can then go back to work with renewed enthusiasm and energy. My college roommate, Dr. Linda Himot, a psychiatrist in Pittsburgh, who has a talent for 10-minute catnaps between patients, says these respites help her focus better on each patient's problems, which are not always scintillating. And companies that encourage napping report that it reduces accidents and errors and increases productivity, even if it shortens the workday a bit. Studies have shown that sleepy workers make more mistakes and cause more accidents, and are more susceptible to heart attacks and gastrointestinal disorders.

A NASA scientist's study showed that 24-minute naps significantly improved a pilot's alertness and performance on trans-Atlantic flights. (The co-pilot remained awake.) Dr. David Dinges, a sleep researcher at the University of Pennsylvania, is a strong advocate of prophylactic napping -- taking what he and others call a "power nap" during the day to head off the cumulative effects of sleep loss. He explained that the brain "sort of sputters" when it is deprived of sufficient sleep, causing slips in performance and attentiveness and often resulting in "microsleeps" -- involuntary lapses into sleep, in which accidents can occur.

A brief afternoon nap typically leaves people feeling more energized than if they had tried to muddle through without sleeping. Studies have shown that the brain is more active in people who nap than in those who don't sleep during the day.

Dr. Maas, the Cornell psychologist and author of "Power Sleep" (Villard Books, 1998), points out that naps "greatly strengthen the ability to pay close attention to details and to make critical decisions." He also states that "naps taken about eight hours after you wake have been proved to do much more for you than if you added those 20 minutes onto already adequate nocturnal sleep."

There are two kinds of naps: brief ones taken to revive the brain and long ones taken to compensate for significant sleep loss. The reviving workday nap should not be longer than 30 minutes; any more and the body lapses into a deep sleep, from which it is difficult to awake.

How and When to Nap

Long naps help when you've accumulated a considerable sleep debt -- for example, when the previous night's sleep was much shorter than usual, or when you know you will have to be alert and awake considerably later than your usual bedtime. I usually try to nap for an hour or more before attending a play, concert or late party. But long naps have a temporary disadvantage: they cause what researchers call sleep inertia, a grogginess upon awakening that can last about half an hour. Also, long naps can affect the body's clock, making it more difficult to wake up at the proper time in the morning.

As Dr. Maas maintains, "Brief naps taken daily are far healthier than sleeping in or taking very long naps on the weekend." They are also far better than caffeine as a pick-me-up. "Consumption of caffeine will be followed by feelings of lethargy and reduced R.E.M. (or dream) sleep that night," Dr. Maas writes. "A debt in your sleep bank account is not reduced by artificial stimulants."

He suggests that naps be scheduled for midday because late-afternoon naps can cause a shift in your biological clock, making it harder to fall asleep at night and get up the next morning. To keep naps short -- 15 to 30 minutes, set an alarm clock or timer. Westclox makes a gadget called Napmate, a power-nap alarm clock that has a one-button preset so you can program your nap to last for a specific number of minutes. If you can lie down on a couch or bed, all the better. If not, use a reclining chair. You need not follow Churchill's advice to get undressed, but make yourself as comfortable as possible. Lap robes are very popular and inexpensive; if a blanket helps you to doze off, use one.

Try to take your nap about the same time each day. Dr. Maas recommends a nap eight hours after you wake up (in the middle of your day, about eight hours before you go to bed at night). Even on days when you don't feel particularly sleepy, he suggests taking a rest rather than a coffee break at your usual nap time.

There are special cases. People who have trouble falling asleep at night might be wise to avoid daytime naps. Parents of newborns should nap when the baby does, rather than using all the baby's sleep time to do chores.

Finally, naps are often essential for people trying to work through illness, injury or chemotherapy, even if they get adequate sleep at night. A woman I know who continued working while receiving cancer therapy napped each day on the floor under her desk. Like so many workplaces, hers had no suitable place to rest.

Copyright 1999 The New York Times Company
Tuesday, January 4, 2000
Science Section
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