It is one thing to know why older people don't sleep as well; it is quite another to do something about it. There is no easy solution because the aging process proceeds at a different pace in different people and affects each of us differently. If you are one of the 35 million Americans who has trouble sleeping, remember that age is not the only culprit. Here are some general measures to help you get sleep, no matter how old or how young you are:

Exercise regularly, preferably aerobically, for twenty to thirty minutes in the late afternoon, but not during the four to six hours before bedtime, and never just before you go to sleep. You sleep better when your body temperature is low, and exercise raises it. Body temperature normally rises during the day and falls at night, but in someone with insomnia, there is less temperature spread; they are not as warm in the daytime or as cool at night. If you warm your body with a workout in the late afternoon, it will cool down when you are ready for sleep.

Don't smoke before bedtime. Nicotine is a stimulant; it raises blood pressure, makes the heart beat faster, and causes your brain to be more active.

You may satisfy your hunger pangs with a light snack at bedtime, but avoid heavy, spicy, or high-fat foods. They increase gastric acidity and give you indigestion.

Keep your bedroom a little cooler than the rest of your home. You will sleep better when your body temperature drops a little. In the summertime, your bedroom should be air-cooled, if possible. It should also be dark. If it isn't, wear eyeshades.

A proper diet low in fat and with lots of salad, fruits, vegetables, whole grain, and fiber will contribute to good health and good sleep.

Remove any clocks that chime or click loudly from your bedroom. If your favorite timepiece isn't noisy, you may keep it in the bedroom, but not where you can see it. You don't want to be reminded, as you toss and turn, how late it is. If you live near an airport or on a busy street, buy yourself some earplugs. Soundproof windows are expensive, and won't do much good if you open them for fresh air during the night.

Go to bed and wake up at approximately the same time every day wherever possible. Your body likes a regular schedule, whether it is eating, moving your bowels, or sleeping. Don't sleep in on weekends, despite how tempting it is. Doing so can upset your body clock.

Before resorting to sleeping pills, ask your doctor to refer you to a sleep clinic where experts can identify and correct your specific sleep problems. For example, they may find out that you have sleep apnea. You should suspect this disorder if your spouse or bedmate complains of your snoring or says that your breathing is irregular and interspersed with long pauses. Sleep apnea can be corrected by a variety of techniques, ranging from simple flow of air into your nose in order to keep the air passages open to surgical removal of excess tissue in your throat that interferes with breathing.