To make matters worse, older people are more likely to take a number of medications that may adversely affect sleep. Common medications, such as antidepressants (prescribed for depression) and antihypertensives (prescribed to control high blood pressure), may have a negative impact on sleep.

Caffeine taken too late in the day (in coffee, tea, soda, chocolate) may lengthen sleep latency, the amount of time it takes one to fall asleep. Alcohol may speed sleep onset but leads to disrupted sleep later in the night.

Nicotine, too, has been linked to sleep problems. In one study, smokers were much more likely than nonsmokers to report problems falling, and staying, asleep along with daytime sleepiness. Another study found that smokers are four times as likely as nonsmokers to suffer from sleep apnea. Nicotine withdrawal, too, can lead to short-term sleep problems - namely, increased awakenings along with a shorter period to fall asleep. Increased daytime sleepiness may follow.

Use of a skin nicotine patch may also be associated with early morning awakenings and reduced total REM sleep, still another study suggests. Once the patch was removed, the length of time before REM sleep - and the percentage of REM sleep - were reduced.

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