You're not sleeping well. You're taking longer to drift off, snapping awake at 2 a.m., then finding it harder to sink back into slumber.

If you think this is normal when you're older, you're mistaken.

A decade's worth of scientific research shows that, yes, sleep changes in older adults. We get less deep sleep and less dream-filled shut-eye. Our biological clocks reset, leading us to bed earlier and to awake with the birds.

Aches and pains can keep us tossing and turning, as can medications we're taking. If we're women of a certain age, hot flashes and bathroom runs can be nightly annoyances. So it goes, also, for men with enlarged prostates.

But these sleep disturbances are treatable, experts say.

Most of the time, a change in sleep habits will do the trick. Drugs that help people sleep are recommended only if other strategies fail and only on a short-term basis.

"Growing older doesn't mean sleeping poorly, and sleep disturbances shouldn't be considered part and parcel of aging," says Michael Vitiello, a professor of psychiatry at the University of Washington.

Evidence-based recommendations for addressing sleep disorders in older adults, published late last year in the Journal of the American Geriatrics Society, are the latest significant contribution to the science of sleep in seniors.

The guidelines encourage doctors to routinely ask older men and women about sleep problems. Patients should take responsibility, also, and bring up any complaints.

Research reports indicate that 57 percent of older adults experience sleep disruptions such as unsettling periodic limb movements (45 percent), insomnia (29 percent), obstructive sleep apnea (24 percent) and early-morning awakening (19 percent). Last year, a Gallup survey of more than 1,000 Americans age 50 or older found that 25 percent believed they had a "sleep problem."

A common cause of difficulties can be medications taken for other illnesses. Some of these drugs act as stimulants, making it difficult for a person to get shut-eye at night; some act as sedatives, causing excessive tiredness during the day.

People can minimize the impact by switching to another drug, changing the dose or simply shifting their medication schedule.

For instance, it's probably better to take a diuretic for high blood pressure in the morning so you're not running to the bathroom at night, says Dr. Harrison Bloom, an author of the new recommendations and an associate clinical professor at Mount Sinai Medical School in New York City. Similarly, it may be advisable to take a narcotic for chronic pain at day's end so you can turn in as you start becoming drowsy.

Other common causes of sleep disturbances include too much caffeine or alcohol, too little exercise or exposure to bright light, and untreated medical conditions such as arthritis or depression. How old your mattress is, how warm your room is at night, how much light comes in through your window — these can make a difference too.

Try changing sleep habits and conditions before taking sleep medications, which can be habit-forming and have other unwanted side effects such as excessive grogginess the next day, experts advise. But realize you may need short-term assistance from a counselor.

"Implementing behavioral changes is very difficult for people to do without help," said Dr. Cathy Alessi, a sleep expert at the Veterans Administration Greater Los Angeles Healthcare System.

Whether the need for sleep diminishes with age is a topic of ongoing debate. Educational materials from the National Institutes of Health suggest that seniors need seven to nine hours of sleep a night, about the same as younger adults. But Scott Campbell, director of the laboratory of human chronobiology at Weill Cornell Medical College in New York, says some research suggests otherwise.

In a small experiment involving 50 people observed in a sleep laboratory, Campbell found that older adults slept about two hours less than people 30 or younger and almost a full hour less than people in middle age. The study was published in 2007 in the Journal of Sleep Research. Similarly, a 2008 report in Current Biology found that older adults (age 60 to 72) slept 7.5 hours a night on average, compared with nine hours a night for people age 18 to 32.

What's increasingly clear is that for the elderly, insufficient sleep is linked with medical concerns such as hypertension, depression, diabetes, heart disease and stroke. "If you have a sleep disorder, the chances of developing one of these conditions is heightened," Bloom said. "And conversely, if you have one of these diseases, the chances of developing a sleep disorder are higher."