Both age and menopause are conspiring to rob you of the sleep you need. Although you once enjoyed a solid eight hours a night, you may be so exhausted now that you would happily settle for a meager five or six. Well, that dream is still possible, but increasingly difficult as you get older. Here's why. Sleep can be divided into two phases: rapid-eye-movement (REM) sleep and non-REM sleep. You alternate four or five times a night between these phases. The non-REM phase is divided into four stages, progressing from light to deep sleep. This pattern is called sleep architecture, and it changes over time. As you get older, you spend less time in deep sleep and more time in the lighter levels of sleep, where you can be awakened more easily by a barking dog or a newspaper tossed on your front porch.

After the age of 50, women are more likely than men to complain about lack of sleep. That's not because they're kvetches. Women are generally more sensitive to the mood alterations caused by lack of sleep. In laboratory studies, older women's estimates of their sleep quality were much more accurate than men's. Certain sleep disorders are also more common in older women. These include sleep-disordered breathing, which is characterized by loud snoring. (Yes, women do snore, although men usually get all the flak for it.) Women who are overweight and physically inactive are more likely to suffer from this disorder; women who've undergone surgically induced menopause are also at higher risk.

If you're struggling with lots of hot flashes during the day, these may also be waking you up at night. Fluctuating estrogen and progesterone production may disrupt sleep because of the effect of these hormones on breathing, stress reaction, mood and body temperature (apart from hot flashes). Some animal studies indicate that these two hormones could also play a role in setting circadian rhythms (the sleep-wake cycle).

If your sleep problems have lasted more than a week or two, get a physical to rule out underlying medical conditions such as thyroid disease or heart problems that can disrupt slumber. If you're basically healthy, your doctor will probably suggest that you start by improving your "sleep hygiene." That's the lingo sleep experts use to describe behavior that affects how easily you fall and stay asleep. An important first step is to use your bedroom only for sleeping and sex, not for watching TV or paying bills. You want to train your brain to slow down at night. If hot flashes are keeping you up, buy a lightweight cotton blanket that you can toss off easily. You might want to swap your flannel pajamas for loose clothing made of high-tech fabrics that breathe like natural fibers but don't absorb moisture (brand names include Coolmax, Dri-release, CoolBest and Under Armour). Some women aim a fan at their side of the bed so they don't disturb their partners. Try cutting out caffeine--or at least avoid coffee, tea and caffeinated soda after lunchtime.

Pay attention to light and dark. A daily dose of sunshine encourages your body's production of the hormone melatonin, which will help you maintain your natural circadian rhythms so you stay alert during the day and are more likely to sleep at night. Some people are also extremely sensitive to the smallest amount of light at night. Even the glow from a clock radio can distract you from sleeping (turn it away from you and see what happens). Cutting down on light in the hours before bed tells your brain it's time to sleep.