L ying awake at night. Waking up too early. Feeling drowsy during the day. As we grow older, these and other sleep problems can become more than major annoyances. They can jeopardize our health.

Sleep deprivation can cause diminished performance, apathy and drowsiness. Falling asleep at the wheel is now known to contribute to an estimated 4% of all fatal automobile accidents.

What can be done to curb sleep problems? You may have heard that it’s important to cultivate good sleep habits. But few people realize just how important proper “sleep hygiene” really is. The basics...

Go to bed at the same time each night and wake up at the same time each morning.

Take a hot bath or perform some other relaxing ritual 30 to 60 minutes before bedtime.

Make sure that your pillow, blanket and mattress are comfortable... and that your bedroom is dark and quiet. Most people sleep best when the room temperature is around 65° F.

Banish computers and other reminders of work from your bedroom.

Avoid caffeinated beverages for six hours before bedtime. Alcohol in moderation is okay, as long as it is not having a negative impact on sleep.

Avoid exercise for three hours before bedtime. Working out early in the day is relaxing, but working out before bed boosts alertness.

If revamping your sleep hygiene fails to improve your sleep, try these strategies...

Take steps to alleviate worry. Worry has a way of descending at bedtime. To keep this from happening, spend a few minutes after supper jotting down your concerns -- and composing your “to do” list for the next day. Then relax until you go to bed.

Go to bed only when you feel sleepy. Your biological clock sends out wake-up messages twice a day -- one in the morning, another in the late afternoon. Trying to sleep before the second message has worn off -- a process that can take an hour or more -- can result in insomnia.

If you tend to fall asleep early and wake up before dawn, your biological clock may be running fast. To overcome this problem, try taking melatonin in the morning or exposing yourself to bright light late in the day.

Ordinary household lights don’t work. You’ll have to sit in front of a lightbox, such as those sold by The SunBox Company (800-548-3968) and Bio-Bright, Inc. (800-621-5483).

Spend less time in bed. If you typically spend eight hours in bed -- but spend two of those worrying about being awake -- try staying in bed for six hours instead.

Odds are you’ll get the same amount of sleep -- but will feel less frustrated. That’s significant, since insomnia-related frustration often sets the stage for even greater sleeplessness.

Watch out for too much sleep. If you pay off your entire “sleep debt” each night, your sleep drive is weakened and you may sleep poorly the next night.

Getting slightly less than a full night’s sleep means that you carry some sleep debt into the next day -- and sleep more soundly that night. Ten to 20 minutes of sleep debt should keep you sleeping well. More than that leaves you drowsy the next day.

Consider physiological causes of sleep trouble. Thirty million Americans suffer from obstructive sleep apnea, a condition marked by repeated pauses in breathing during sleep.

These pauses -- up to 200 a night -- make it impossible to get deep, restorative sleep. Most cases of sleep apnea are caused by excessive tissue in the back of the throat. At night, this tissue collapses onto the trachea, shutting off the flow of air until the sleeper gasps and then resumes breathing normally again.

Apnea sufferers tend to snore heavily -- and to snort periodically as they sleep. If you suspect that you have sleep apnea, consult a doctor.

In many cases, apnea can be controlled with continuous positive airway pressure (CPAP), in which an air mask worn at bedtime continuously pumps air and regulates pressure. For those unable to tolerate the mask, surgery may be necessary.

Another physiological condition that causes daytime drowsiness is narcolepsy. People with narcolepsy nod off abruptly during the day -- sometimes while walking or driving.

A new prescription drug called modafinil (Provigil) curbs episodes of narcolepsy without causing jitters, palpitations and the other side effects associated with amphetamines. Until recently, amphetamines were the only effective treatment for narcolepsy.

Take steps to control restless legs. Restless legs syndrome (RLS) causes a creeping, pulling sensation in the legs, particularly at night. The urge to move the legs makes it almost impossible to fall asleep. If you think you might have RLS, ask a doctor about carbidopa-levodopa (Sinemet) and gabapentin (Neurontin). These prescription medications are highly effective at curbing RLS.

Consider the possibility that you’re depressed. Early-morning awakening is a hallmark of depression -- and, to a lesser extent, of anxiety.

See your doctor if symptoms of these disorders, including hopelessness and worthlessness, persist.

Watch out for drug-induced insomnia. Many different medications, including some antidepressants and heart drugs, can cause insomnia.

If you take any medication regularly, ask your doctor if it might be interfering with your sleep. If so, he may be able to alter the dosage or switch you to another medication.

Consider sleeping pills. Short-term use of a sleeping aid is often helpful -- especially during periods of stress. The prescription drug zolpidem (Ambien) is highly effective and is far less likely to cause addiction than barbiturate sleeping pills.

Over-the-counter sleeping aids seem to be effective but have not been carefully studied.