Jewish World Review April 9, 2003 / 7 Nisan, 5763

Feeling sleep-deprived? try a "power nap'' and bedtime routine

By Marlene Cimons | Sleep deprivation is not the same as jet lag, although it, too, can wreck your body and your mental sharpness. Jet lag is the catch-all term for the disruption of your body's "clock,'' caused by crossing time zones. Sleep deprivation is when you just don't get enough sleep, for whatever reason.

The amount of sleep a person needs changes over time. Newborns sleep 50 percent of the time. As people grow older, their need for sleep declines; most adults need between seven and nine hours on average.

"The general rule,'' says Margaret L. Moline, director of the Sleep-Wake Disorders Center at the Weill Cornell Medical Center in New York City, "is that the amount of sleep you need is the amount that allows you to feel fully refreshed and alert all day long.''

But how many people can say they meet this standard? Too few, according to the experts.

Most Americans are sleep-deprived, according to research conducted by the National Sleep Foundation. Most of us get fewer than eight hours a night. Either we just can't get to bed early enough, or our sleep is disturbed or delayed once we get to bed.

"Some people simply don't allow themselves to spend enough time in bed to get the sleep that they need,'' says Moline, "including allowing for falling asleep. Others may have a sleep disorder -- such as sleep apnea (sleep-disordered breathing) or restless legs syndrome -- that makes sleep less continuous and less refreshing. Still others may have symptoms of insomnia, which again can arise from many different causes, including irregular schedules, mood and anxiety disorders, pain, certain types of medication and shift work.''

Parents may also have trouble getting enough sleep because they're to attending to the needs of their children, she says.

Whatever the cause, insufficient sleep is counterproductive and unhealthy, and sometimes even dangerous. People who don't get enough sleep often drive drowsy, and are fatigued at work or at school.

A recent study funded by the National Institutes of Health and conducted by University of Pennsylvania researchers found that people who slept four to six hours a night for 14 consecutive nights showed significant deficits in cognitive performance -- the equivalent, in fact, of going without sleep for up to three days in a row.

The study, published in the March issue of the journal Sleep, reported that subjects nonetheless said they were feeling only "slightly sleepy,'' and were unaware of how impaired they actually were.

"The results provide a clearer picture of the possible dangers to people who typically are awake longer on a regular basis, including members of the military, medical and surgical residents, and shift workers,'' says principal investigator David Dinges. "Reduced cognitive abilities can occur even with a moderate reduction in sleep.''

People had trouble paying attention and reacting to a stimulus, according to the researchers. Other problems included an inability to think quickly and without error, and a reduced ability to "multi-task,'' that is, to hold thoughts in the brain in some order while doing something else.

The consequences of sleep deprivation can also affect physical health. For example, a study published in January in the Archives of Internal Medicine conducted by researchers at Brigham and Women's Hospital in Boston, Mass., found that too little or too much sleep was associated with a moderately increased risk of coronary heart disease in women. This is especially disturbing since women typically average seven hours of sleep on weeknights, compared to 6.7 hours a night for men, according to a 2002 poll conducted by the sleep foundation. Women are also much more likely to report having symptoms of insomnia than men (63 percent vs. 54 percent), and frequent daytime sleepiness (20 percent vs. 13 percent).

In addition, more than one-quarter of the women surveyed said they get less sleep than they need in order to be fully alert the next day.

Some have found what many countries have known for years -- that an afternoon siesta (or "power nap'') can go a long way toward easing sleep deficit and boosting performance. Research conducted by Alan Hobson, Robert Stickgold and Sara Mednick, all physicians at Harvard University, and published last July in the journal Nature Neuroscience, showed that an afternoon snooze can reverse information overload.

"We should stop feeling guilty about taking that power nap at work,'' the researchers said in a statement released by the National Institute of Mental Health, which funded the work.The scientists reported that "burnout'' -- irritation, frustration and poorer performance on a mental task -- set in as a day of training wore on.

Subjects were asked to perform a visual task -- reporting the horizontal or vertical orientation of three diagonal bars against a background of horizontal bars in the lower left corner of a computer screen. Their scores worsened over the course of four daily practice sessions.

But a 30-minute nap after the second session prevented further deterioration -- while a 60-minute nap actually enhanced performance in the third and fourth session, returning them to morning levels.

Rather than generalized fatigue, the researchers theorized, the burnout was due to information overload, and was limited to just the brain visual system circuits involved in the assigned task. When they changed the location of the task to the lower right corner of the computer screen -- for just the fourth practice session -- the subjects did not suffer the same "burnout'' but performed as well as they had during the first session -- or after a short nap. The researchers think the burnout response may be the brain's way of "preserving information that has been processed, but has not yet been consolidated into memory by sleep.''

In another experiment, the Harvard researchers showed that a 20 percent overnight improvement in learning a motor skill can be traced to a late stage of sleep that early risers might be missing.

In work published last July in the journal Neuron, they reported that specific neural networks in the brain that "fired'' during the critical final hours of early morning sleep contributed to this learning potential, a finding that could be critical to musicians, dancers, athletes and even to those recovering motor functions following a stroke.

Since a full night's sleep is a prerequisite to experiencing those important final hours "life's modern erosion of sleep time could shortchange your brain of some learning potential,'' says Dr. Matthew Walker, one of the investigators.

So how can people get more sleep?

-- Try to establish a regular schedule, whereby you go to sleep and get up at the same time every day. "This will put your body into a good sleep-wake rhythm,'' Moline says.

-- Avoid alcohol, caffeine, chocolate and heavy, sugary or spicy foods, and smoking for several hours before bedtime.

-- Don't exercise in the evenings. Exercise wakes you up and will make it harder to fall asleep. Work out in the mornings or during the day. If you must exercise at night, leave at least three hours between the end of your workout and the time you go to bed.

-- Check your bed. Make sure you have a firm, comfortable mattress, keep the room temperature comfortable, and the room well ventilated. Block out as much light as possible, as well as all distracting noises.

-- Don't use your bed as an office or recreation room; use it only for sleep and sex.

-- Don't underestimate the power of a nap -- but don't nap haphazardly. But sure to take naps on a regular schedule.

"A person needs a certain amount of sleep per day to feel fully alert, and to function optimally,'' Moline says. "Some may find it more convenient to take a nap and sleep less at night. However, just as it is important to maintain a regular bedtime and waking schedule for night sleep, naps should be taken at regular times across the week. Otherwise, you may still feel sleep-deprived.''

Eric Harr is a professional triathlete, author and television host. His latest book is "The Portable Personal Trainer: 100 Tips to Energize Your Workouts and Bring out the Athlete in You''. Comment by clicking here.


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