We hear a lot about the effects of diet and exercise on health, but adequate sleep plays an equally important role.

Studies show that chronic lack of sleep is linked to obesity, diabetes, heart disease and mental health. The less rest and recovery your body gets, the weaker your immune system also become.

Studies show that sleep deprivation can also affect the body’s response to vaccines. When the immune system is suppressed, the bodies’ response is slower to build up sufficient antibodies to fight off the disease. Despite growing awareness of the importance of getting enough shut-eye, 30 percent or more of U.S. adults get fewer than the recommended seven to eight hours a night.

Experts suggest these tried and true tips for a good night’s sleep:

Avoid substances that contain caffeine, such as in chocolate, coffee, teas and soft drinks, as well as nicotine and alcohol too close to bedtime. If you do have caffeine, try to make sure it is no closer than 6 hours before you plan to go to sleep. Alcohol is a depressant that not only interferes with deeper stages of sleep, but relaxes muscles in the throat, increasing chances of snoring and breathing problems. Nicotine is a stimulant, raising blood pressure and elevating the heart rate. Taking sleeping pills on a regular basis can also interfere with sleep cycles, and may create dependency.

Try to establish a regular schedule for going to bed and waking up. Your body functions at its best when set patterns and routines are followed. By adjusting your “time clock” you will be more likely to fall asleep quicker and sleep more soundly.

Set aside the last hour or so of the day as your time to unwind and relax. This will calm you down, and help you to avoid thoughts associated with stressful events of the day.

Keep your bedroom as comfortable, dark and quiet as possible. If you are a light sleeper, try using “white noise” or very soft, soothing music to mask other sounds that might normally wake you up. A firm, supportive mattress and fresh clean sheets can make all the difference.

If you’ve tried everything and you still can’t fall asleep, don’t fight it. Worrying about being awake serves no purpose and just makes matters worse. Instead, listen to your body, go ahead and get up, or spend this time doing some sort of relaxing activity such as reading until you feel sleepy.

Next week: How sleep influences weight.