Summer is supposed to be the season for relaxing, day after sun-soaked day of afternoon naps in a hammock and vacations filled only with the sound of water gently hitting the shore.

But while all that sun and warm weather is great for fun, it's bad for sleeping. The heat makes it hard to get comfortable at night. The long hours of sunlight keeps people out and active later, throwing off their circadian rhythms.

And a vacation's effect on sleep quality can cut both ways. A trip might provide the chance for more — and more restful — sleep, but only if getting away is a big stress reducer. Eliminating daily pressures, such as work deadlines, rush-hour traffic and home duties, can be just the thing to improve sleep quality.

But because changes in environment can disturb sleep, many people experience the opposite. A trip brings on myriad changes: different time zones, unfamiliar mattresses, new schedules and foods, nighttime noises and even the pressure of visiting relatives, to name a few.

"Almost any change of the environment has some degree of effect on sleep quality," says Dr. Damien Stevens, who specializes in sleep medicine at the University of Kansas Hospital.

So don't be sad to see September on the calendar. Maybe that much-needed sleep is finally coming with the cool nights back in your own bed.

Maybe, but although you're likely to sleep better, the change of seasons won't do it on its own. People need to help themselves, too, for a better night's sleep. And they can start by ensuring that the bedroom is a true retreat from the world.

"Your room should be your sanctum sanctorum," says Dr. Adam Glassman, medical director of the new Northern New Jersey Center for Sleep Medicine at Holy Name Hospital in Teaneck. "You should just really associate your room with sleeping. You should try not to do any other activities in it. I know that's hard for a teenagers and adolescents. For adults, certainly, our room should really just be for sleeping and sex."

In general, exercise and increased activity improve sleep quality, but their summer timing can be a sleep killer, when long days allow us to extend outdoor workouts into the evening hours. Many people report they have "pent-up energy" after exercise, and that delays restfulness, says Stevens. Now that the days are getting shorter, it's a good idea to end workouts at least two hours before going to bed. Some people need four or even six hours between exercise and bedtime.

"Good sleep hygiene," as Glassman puts it, also includes lowering the lights in the bedroom, which prompts the body to produce sleep-inducing melatonin. Ideally, you should remove the television and computer from the bedroom. Not practical? Try covering them with a pretty scarf or other fabric.

So it's dark, cool, quiet and peaceful in your room … but how long will you actually sleep? It may be time to face reality — four or five hours of sleep each night is not enough. Very few of us can enjoy 19 or 20 waking hours each day feeling good and functioning at our best.

"Everybody's a little bit different, but … probably 95 percent of the people do need seven to eight hours of sleep a night," says Glassman, who adds that adolescents need more.

"There is a certain very small subset of people that do require less sleep, the short sleepers," he says. "But that's really probably been exaggerated. Most people would be healthier and happier if they got eight hours of sleep."

Better sleep tips

The key to being well-rested is good "sleep hygiene." Here are some tips:

• Go to bed and wake up at the same time every day, including weekends.
• Avoid computers, smartphones, etc. for an hour or two before going to bed.
• Do not watch TV in bed or fall asleep with the TV on.
• Keep the bedroom as dark — and peaceful — as possible.

Seek evaluation from a sleep center or specialist if you have any of the following symptoms:

• Chronic fatigue for more than three months.
• Trouble falling asleep and/or maintaining sleep for an extended period of time.
• Frequent snoring, with others noticing that you stop breathing while sleeping.

Source: Dr. Adam Glassman, medical director of the Northern New Jersey Center for Sleep Medicine at Holy Name Hospital.

E-mail: yoriok@northjersey.com. This article contains material from news service reports.