Alcohol, caffeine, and nicotine can have a powerful effect on sleep, so too does the environment in which you sleep.
As alcohol is depressant that relaxes the brain, it can make the descent into sleep much easier. Nonetheless, alcohol can make sleep lighter and more fragmented as well, for it suppresses deep sleep and dream sleep by impairing the functioning of the sleep system. As a result, we are more likely to awaken feeling un-refreshed. Alcohol also disturbs sleep because, as it is metabolized during sleep, it produces mild withdrawal symptoms that cause sleep to become interrupted, shortened, and fragmented (See the Truestar Sleep archives for more information on sleep). These disruptions result in lighter sleep and more awakenings, particularly in the early morning. Alcohol also exacerbates snoring and sleep apnea because it relaxes the muscles in the throat.
It requires about one-and-a-half hours to metabolize one ounce of alcohol; the mild withdrawal effects last for another two to four hours. This means that a glass of wine with dinner will probably not affect sleep. However, one ounce of alcohol within two hours of bedtime or more than one ounce after dinner will disrupt sleep. Therefore, if you drink alcoholic beverages in the evening, you will minimize sleep problems if you limit yourself to one drink at least two hours before bedtime.
Caffeine is a stimulant that speeds up brain waves, increases heart rate and blood pressure, promotes alertness and reduces fatigue. These stimulant effects, which work in as little as 15 minutes and can last for six or more hours, can also disturb sleep. Caffeine can also produce daytime anxiety (see the Truestar Attitude archives for more techniques on managing anxiety and stress) symptoms such as nervousness, irritability, shakiness, and sweaty palms; and, also cause more frequent nighttime urination that may interrupt sleep.
We vary greatly in our sensitivity to the stimulant effects of caffeine. Some of us have a natural tolerance to caffeine and can fall asleep after drinking two cups of coffee in the evening, while others have trouble sleeping after drinking one cup of coffee in the afternoon. Generally, it takes about five hours to metabolize half the caffeine you have consumed. Meaning, if you drink 150mg of caffeine at noon (one large cup) you will still have 75 mg in your body at 5:00 p.m. It takes another five hours to metabolize half of the remaining 75 mg, which means that you will still have about 35-40 mg of caffeine in your body at 10:00 p.m.enough to disturb your sleep. Therefore, avoid caffeine after lunchtime.
The effects of nicotine are similar to caffeine and include faster brain waves, heart rate, breathing rate and increased stress hormones. These stimulant effects, which last for several hours after smoking a cigarette, can make it harder to fall asleep and stay asleep.
Smokers will have the greatest beneficial effect on sleep if they stop smoking altogether.
Numerous studies have shown that, when smokers quit, they sleep better in spite of temporary withdrawal symptoms like restlessness, irritability, anxiety, difficulty concentrating and headaches, which can last for about ten days. Once the withdrawal symptoms end, sleep improves even more dramatically.
Only a small percentage of smokers quit smoking permanently, and those that do usually do it "cold turkey." If a smoker can't quit, he should try to eliminate smoking near bedtime or during the night. This will minimize the stimulant and withdrawal effects of nicotine on sleep.
The Proper Sleep Environment
There are three important ingredients to a proper sleep environment: coolness, quiet, and darkness. Insomnia is associated with a failure of body temperature to fall either at bedtime or during the night. By sleeping in a warm room, body temperature will have an even harder time falling. This will make it more difficult to fall asleep, and because deep sleep will also be reduced, nighttime awakenings will be more likely to occur.
On the other hand, body temperature shows a more rapid drop in cooler rooms. In fact, the lower the room temperature at which we go to sleep, the greater the drop in body temperature and the easier it will be to fall asleep and stay asleep. So keep the bedroom cool by turning the heat down, leaving a window open, or using a fan or air conditioner.
Because many types of noise can disturb sleep, there are a number of ways to minimize bedroom noise. Earplugs work well for many people. For others, the hum of a fan, an air conditioner, or a commercially available sound conditioner is useful. These devices work by blocking distracting noises and by producing constant, soothing sounds like water or rain that relax the brain and induce sleep.
A bedroom that is insufficiently dark can also disturb sleep. The bedroom should be kept dark by using drapes, heavy shades, or an eyeshade if necessary.
Finally, consider the size of the bed you sleep in and whom you sleep with. We go through up to a dozen posture shifts per night in which we awaken briefly, move, then quickly fall back to sleep. When we sleep with a bed partner, we also awaken briefly in response to their posture shifts. Even though many people think they sleep better with a bed partner, sleep is actually lighter, more restless and more disturbed.
If you sleep with a bed partner, particularly one that is a restless sleeper, your sleep will be less disturbed if you switch to a bigger bed or twin beds. If your bed partner is a heavy snorer, separate bedrooms may be necessary if he or she is unwilling to seek medical treatment.