Reasons You Can't Sleep And What to Do About Them

1: Too Much Coffee
Caffeine blocks the sleep-inducing action of the brain chemical adenosine. It can also reduce the amount you make of the sleep hormone melatonin. Not only will it lead to trouble dropping off, but also you'll sleep restlessly. In an Israeli study, subjects given caffeinated coffee had about half as much melatonin in their systems as those who were given decaf. They also took twice as long to fall asleep and slumbered an average of 79 minutes less.

The fix: Drink early, but not often. Limit caffeine consumption to 250 milligrams a day (about 16 ounces of coffee), the amount most of us can handle without it causing bedtime troubles. It takes about six to eight hours for your body to clear enough caffeine to avoid its interfering with your sleep, so put your cup down by 2 P.M.

2: Too Much Light 

While playing a few rounds of Words With Friends on your iPad or spending two hours in front of the tube may help you wind down, your body's response to the short-wave blue light emitted by these devices' backlit screens is, "Hey, more daylight! Let's stay up and play." (This is true for compact-fluorescent, LED, and incandescent lights, too.) Sleep hormones kick in at about 9 or 10 P.M., but if the bedroom never gets dark, your body holds off on melatonin production, making it harder for you to fall asleep.

The fix: Say "Ta-Ta" to your tech toys. It may be hard to sacrifice your post-dinner Facebook activity but try to pull yourself away an hour before bed and dim the lights in your house.

3: Restless Legs Syndrome (RLS) 

If you wake up because you have the irresistible urge to move your legs to stop them from tingling, you may have this nerve disorder, which occurs in about 5% of the population. It can also lead to difficulty falling asleep and frequent waking. RLS often runs in families, and like so many other things, it tends to be worsened by stress. Some people with RLS have an additional condition called periodic limb movements in sleep, in which their legs jerk every 20 to 40 seconds in clusters throughout the night.

The fix: Get an RX for RLS. While massages, relaxation exercises, regular workouts, and elimination of caffeine and alcohol can help, your doctor may suggest one of several FDA-approved drugs to treat RLS. Or she might prescribe medications that have been approved to treat other conditions (such as Parkinson's disease), but which also ease RLS symptoms. You might ask your doctor to check your iron levels; anemia can cause RLS.

4: Worry 

Your emotional life is like a set of invisible arms that shake you out of a sound sleep so you can fret a little while longer. "About 75% of the people I see with sleep problems have anxiety or depression," says Breus.

The fix: Count your blessings. In a study conducted by Robert A. Emmons, Ph.D., of the University of California, Davis, people who listed five things they were grateful for each day in a gratitude journal fell asleep faster, slept for longer periods of time, and also woke up feeling more refreshed than those who didn't use such a journal.

5: Pain or Discomfort 
Two major sleep disrupters are back pain and gastroesophageal reflux disease (GERD), a condition in which the ring of muscle fibers (or sphincter) in the esophagus can't prevent a backup of stomach contents into the throat. It occurs during the day, but there's also a nighttime version.

The fix: If you have back pain, when sleeping on your back, use a small pillow for your head; place another under your knees to take pressure off your lower back. When on your side, put a pillow between your knees and thighs.

If you have GERD, raise the head of your bed  or your own torso  with pillows, so you're not lying flat. It may also help to lose weight if you are overweight. In one study, a loss of just 10 to 15 pounds reduced heartburn in women by 40%.

6: Aging 
As people get older, they're more likely to have long periods of wakefulness, often early in the morning. That's because in your '20s and '30s, you start getting less and less of the deepest stages of sleep  "the kind that allows a sleeping child to be lifted out of the car, carried upstairs, and undressed and tucked into bed without waking up. "That's one reason that even healthy older people have sleep disruptions  if you're not as deeply asleep, anything is likely to wake you," like a truck outside or even birds chirping.

Aging, it turns out, may have a smaller impact on sleep than many have thought. A 2010 British study found that older folks slept only about 20 minutes less a night than middle-aged men and women, who in turn slept only 23 minutes less than young adults. What's more, says Duffy, in her research she has found that healthy older people can miss sleep  even stay up all night  and not be as exhausted the following day as someone younger might be.

The fix: Get an early start to the day. It's what many tightly scheduled (and successful) business leaders do. They may use the early morning hours to work out, catch up on e-mail, and read the news before heading out to the office. Remember the old saying "Early to bed and early to rise makes a man healthy, wealthy, and wise"? It goes for women, too.

7: Obstructive Sleep Apnea (OSA)

When you have this serious, widespread condition  it's as common as type 2 diabetes  your breathing stops periodically (sometimes for a minute of times to restart it. OSA is caused by a blockage of the airway, usually when the soft tissue in the back of the throat collapses. Why this cause of your daytime sleepiness can be such a surprise: You've been waking up all night, but with no awareness of its even happening. OSA's major symptom is loud snoring  ask your partner (if he hasn't complained already), or run a tape recorder one night.

The fix: Start that diet you've been talking about. About 65% of people who have OSA are overweight or obese. The condition can contribute to  or be a consequence of  extra pounds. Slimming down often improves symptoms and may even cure your obstructed breathing. If you have mild apnea that occurs only when you lie on your back, try sleeping on your side. One way to keep from rolling back again: Place a tennis ball in a sock, then pin the sock to the back of your PJs.

It might also be time to check in with a pro. Even if your bedmate hasn't said you've been snoring, see your doctor about unexplained and profound daytime sleepiness. If you have OSA, you may need a continuous positive airway pressure (CPAP) machine. It works by not allowing the soft tissue in your throat to collapse and stop your breathing.