Perchance to Dream.

Shut-eye. 40 winks. Catching some Zzzzs. Whatever you call it, sleep is just not as deep, long, or recuperative as many us would like. And a good night's rest only seems to become more elusive as we get older. Is there anything you can eat, drink, or sandman more satisfying?

Food

Most of us are probably convinced that what we eat and when we eat it affects how well we sleep. Yet there's remarkably little research on the subject.

Do some foods make us drowsier than others? Does a nighttime snack help or hurt the odds of getting a good night's sleep? All we have are a few clues from short-term studies on a small number of people who had no sleep problems:

* Young men fell asleep just as quickly within a few hours after a late-afternoon high-fat meal as after a high-carbohydrate meal with the same number of calories.[1] "There are lots of claims about this or that food," says Gary Zammit, director of the Sleep Research Institute in New York. "But nothing stands out as being better than anything else."

* A dinner of ordinary solid food put young men to sleep faster than a liquid dinner with the same number of calories.[1] Interesting; but it's not exactly proof that a handful of crackers will make you sleepier than a glass of milk.

* Young men who were deprived of lunch dozed off afterwards just as quickly as young men who were fed, but those who ate stayed asleep for three times as long.[2] Does that mean that eating helps you sleep or going to bed hungry doesn't? It's too early to say.

If eating helps people sleep, Zammit thinks it's because body temperature rises after a meal. "Changes in body temperature after eating may signal our bodies to feel sleepy," he says.

Supplements

"When evaluating whether a drug or dietary supplement promotes sleep, you look for consistent results from both subjective and objective measurements," says Zammit.

Subjective measurements of sleep--usually questionnaires filled out the morning after--record what the sleepers remembered about their sleep and how rested they felt afterwards. Objective measurements, like EEG recordings of brain waves, verify when and for how long people slept and whether the sequence and depth of the different stages of their sleep were normal.

"If both the subjective and objective results consistently show an improvement in at least some important aspects of sleep, then you're onto something," says Zammit.

Some over-the-counter products --antihistamines like Benadryl, for example --clearly make people sleepy. But what about the "sleep" supplements that promise a restful night? Here are how the two most popular ones stack up:

* Valerian. It's "one of history's most distinguished natural products for promoting restful sleep," says Natrol, which makes Valerian Evening Formula.

And in four of five controlled published studies, participants were more likely to report that at least one aspect of their sleep--such as how long it took to fall asleep or how often they awoke during the night--was better on the nights they took valerian than on the nights they took a (look-alike but valerian-flee) placebo.

But the objective measurements didn't jibe with the volunteers' memories. In the three studies that monitored brain waves in a sleep laboratory, 14 people in their 20s and 30s without sleep problems and 14 women in their 60s who were poor sleepers took 400 mg to 1,200 mg of valerian before bedtime for one to eight nights.[3-5]

EEGs failed to show any improvement in their sleep compared with when they took a placebo. Valerian didn't bring on sleep sooner, didn't reduce the number of awakenings, and didn't diminish the time spent awake during the night. And the older women who had trouble sleeping didn't rate their sleep any better when they were taking valerian.

"The research on valerian is not very impressive," concludes Wallace Mendelson, director of the University of Chicago's Sleep Research Lab.

While researchers haven't seen any side effects from valerian, the longest controlled study lasted just three weeks and involved fewer than ten people. So its long-term safety is unknown.

* Melatonin. "Provides Baby-like Sleep," claims the Web site for Healthness Natural Foods (www.healthness.com/ insomnia.htm).

Melatonin is a hormone that helps regulate our daily cycle of sleeping and waking. Some people, especially older people who have trouble falling and staying asleep, may produce too little melatonin or release it at the wrong time. Would taking melatonin before bedtime help them?

"Most studies find a small benefit in helping people fall asleep faster," says Cliff Singer, Medical Director of Geriatric Psychiatry at the Oregon Health Sciences University in Portland.

"But no one has shown that replacing the amount of melatonin found naturally in the body has any effect on keeping people asleep, increasing deeper slow-wave sleep, or reversing other changes in sleep that occur with age," he adds. "And there's been no evidence that alertness the day after is increased, which would be expected from any effective sleep therapy."

Older people may need higher-than-natural levels of melatonin to feel an effect, says Singer. "But just how high, we don't know yet."

Melatonin was recently tested to see if it could help regulate the sleep schedules of space shuttle astronauts. It didn't work, researchers reported last spring.

Is melatonin safe? "No serious detrimental effects have been reported even at high doses--more than 0.5 mg--when used for short periods of time," says Singer. "But no systematic long-term trials have been performed."

Last year, researchers at the Mayo Clinic in Rochester, Minnesota, reported finding a contaminant in some batches of melatonin supplements. It's similar to a contaminant that was found in tryptophan supplements ten years ago that caused a painful and potentially deadly illness called eosinophilia myalgia syndrome (EMS). No cases of EMS have been linked to melatonin.

Sleep-Busters

* Alcohol. Ask people what they use to fall asleep and the most common answer is probably "alcohol." But the apparent benefit of a nightcap may be an illusion.

"If you drink alcohol close to your bedtime, it can disturb your sleep," says Timothy Roehrs of the Sleep Disorders and Research Center of the Henry Ford Hospital in Detroit.

"Alcohol can help people fall asleep and it actually increases the depth of their sleep during the first four hours," adds Roehrs. "But tolerance to the effects of a moderate amount of alcohol develops very rapidly. Then you have to drink more and more to get the same results, until you reach the point where the alcohol starts disrupting your sleep and increasing the amount of wakefulness during the second half of the night."

Roehrs's advice: "People who drink socially and notice that on those nights they awaken in the second half of the night should avoid alcohol before their bedtime."

Women's sleep is probably more disrupted by alcohol than men's, says Roehrs, since their smaller body size and slower metabolism of alcohol mean that they get a greater effect from the same number of drinks.

"The sleep of older people is also more disrupted by alcohol," says Roehrs, "because their sleep is lighter" (see "Sleep & Aging").

* Painkillers. Some painkillers can interfere with a good night's sleep. "When we gave aspirin or ibuprofen (like Advil) at 8:15 a.m. and 11:00 p.m. to men and women who were in no pain, they awakened more often and spent more time awake during the night than when we gave them acetaminophen (like Tylenol) or a placebo," says Patricia Murphy of the Laboratory of Human Chronobiology at the New York Hospital/Cornell Medical Center in White Plains, New York.[6]

What's different about aspirin and ibuprofen? "Our follow-up study found that they blunt the normal drop in body temperature at night and suppress the release of melatonin, both of which normally promote sleep," says Murphy.

So if you have a headache at night, try taking acetaminophen instead of aspirin or ibuprofen. Just keep in mind that acetaminophen doesn't work for inflammation or rheumatoid arthritis pain. And if you take aspirin every day to help reduce your risk of heart disease, take it early in the day.

* Caffeine. Adults begin switching from regular coffee to decaf at about age 50, according to a recent survey of 3,000 residents of the Southern California community of Rancho Bernardo.

But moving to decaf may not be enough to ensure a restful night's sleep. In the Iowa 65+ Rural Health Study of 3,000 older men and women, those who took over-the-counter medications containing caffeine (like Excedrin or Anacin) were almost twice as likely to have trouble falling asleep than those who took the same medications without caffeine.[7]

Caffeine is also found in Coke, Pepsi, and some non-cola drinks like Sunkist and Mountain Dew. And some coffee yogurts and ice creams have enough to keep many people tossing and turning.

Sleep-Inducers

* Regular Exercise. "People who exercise regularly fall asleep faster, sleep for a longer time, spend less time awake during the night, and get more deeper slow-wave sleep than people who don't exercise," says exercise researcher Karla Kubitz of Towson University in Maryland.

"When our body temperature begins to cool down, which usually occurs late in the evening, it may be a signal that it's time for us to feel sleepy," says Kubitz. "Exercise may help people sleep by warming up our bodies, which then cool down as a result."

When Kubitz pooled the results of 12 different studies, she found that women and older people seem to get the most benefit from exercise.[8] "That's probably because they typically have more sleep problems, so they have more room for improvement," she says.

Indeed, physical activity has been used to help middle-aged and older people who have trouble falling asleep at night.

"We arranged for a group of people with moderate sleep complaints to attend a low-impact aerobics class twice a week and to go out for a brisk 40-minute walk twice a week,' says Abby King of the Stanford Center for Research in Disease Prevention.[9]

"After four months, they were falling asleep in half the time, sleeping 50 minutes longer than they did before, and reporting feeling more rested in the morning."

Does it matter when you exercise? "The earlier in the day, the bigger the increase in deeper, slow-wave sleep," says Kubitz.

* Baths. A hot bath before bedtime raises the body's temperature, and the subsequent cooling may trigger sleep. In the first study of baths for the treatment of insomnia, nine women insomniacs in their 60s and 70s took hot baths an hour and a half before bedtime.[10]

"The women reported deeper sleep, less restlessness during the night, and more restedness in the morning after a hot bath than after a bath at body temperature, which they perceived as cool," reports Cynthia Dorsey of the Sleep Disorders Center and Sleep Research Program at McLean Hospital in Belmont, Massachusetts. Measurements of brain activity confirmed that the women awakened less during the night.

[1] Physiol. Behav. 62: 709,1997.

[2] Sleep 18: 229, 1995.

[3] J. Psych. Res. 17:115, 1982.

[4] Psychopharm. 87: 406, 1985.

[5] Pharmacopsych. 27:147, 1994.

[6] Physiol. Behav. 55:1063, 1994.

[7] J. Amer. Geriat. Soc. 43: 860, 1995.

[8] Sports Med. 21: 277, 1996.

[9] J. Amer. Med. Assoc. 277: 32, 1997.

[10] J. Geriat. Psych. Neurol. 9: 83, 1996.

RELATED ARTICLE: SLEEP & AGING

"For many years, we've known that sleep in older people is very different from sleep in younger people," says Julie Carrier of the Sleep Center at the Sacra-Coeur Hospital in Montreal. "Starting at 30 years of age, complaints about sleep increase, and they continue into a person's 80s."

There's a reason for that. "Older people have almost no slow-wave sleep," she says. "That's the deepest stage, when people sleep very, very soundly. What's more, as you age you wake up more often and have more trouble getting back to sleep."

Older people also have problems adapting to changes in sleep time, says Carrier. "They have a lot more complaints about the effects of shift work or jet lag. We believe that the sleep-wake cycle becomes more fragile, more vulnerable to disruptions."

Then there's menopause. "Hot flashes aside, complaints about sleep are one of the biggest problems reported by menopausal women," says Carrier. "Yet there are very few objective studies that try to understand why women have so many problems falling and staying asleep during menopause."

What can older people do to improve their sleep? "Try to take care of your sleep-wake cycle," says Carrier. "Go to bed and get up at the same time each day."