There's hardly anything more unpleasant than having trouble sleeping night after night. Tossing and turning, waking up exhausted - it's a miserable thing.

Our bodies need sleep. Studies have shown that sleep deprivation is quite harmful to the body, and after only a little while without sleep, symptoms like headaches, dizziness, confusion, and even hallucinations can develop.

When someone has constant trouble falling asleep or staying asleep, that disorder is called insomnia. Some sufferers of insomnia wake up frequently during the night and have trouble going back to sleep. Others can't fall asleep when they first go to bed. They wake up in the morning feeling tired.

Some insomnia is caused by other health conditions, such as heartburn, medications, depression, asthma or other breathing problems, or chronic pain. But some insomnia doesn't seem to have a cause, making the problem hard to address.

Some people find that insomnia comes and goes, with good nights interspersed with bad. Others struggle with it for extended periods of time.

Here are a few tips for managing insomnia:

• If you smoke, try to stop, at least in the evening, and avoid alcohol and caffeine as well. Nicotine, alcohol, and caffeine all act as stimulants on your nervous system, and might be keeping you awake.

• You may have heard if you can't sleep, you should get up instead of tossing and turning. But this may not actually be true. Lying in bed is a cue to your body that it's time to sleep, and even if you aren't asleep, your body is getting some rest. If you do get up, keep the lights low and do something quiet, such as reading. Studies show that bright lights can trigger the body to produce adrenaline, a natural stimulant-and the last thing you need if you're trying to fall asleep.

• Don't eat a heavy meal late in the evening. A light snack may be a good idea, though, and may even help you stay asleep longer.

• You may feel reluctant to use sleeping medication, but doing so can help reset your sleeping cycle and get your body accustomed to falling asleep at the right time. There are several types of medication available, either by prescription or over-the-counter. If one medication doesn't work for you, another may.

• Be careful about naps. If you haven't slept well the night before, the desire to nap may be almost irresistible. But giving in to that urge may prolong the cycle of poor sleeping. Hopefully, if you can manage to stay awake until your normal bedtime, sleep will come more easily and you can get re-regulated. Some sleep doctors help correct insomnia by keeping their patients awake for long periods. To a certain extent, you can try this for yourself.

If none of these tips help you get the rest you need, then the insomnia might be indicative of a more serious problem. Be sure to consult your physician if you think that this might be the case.