Do People Need Less Sleep As They Age?
We all look forward to a good night's sleep. Sleep allows our body to rest and to restore its energy levels. Without enough restful sleep, not only can we become grumpy and irritable, but also inattentive and more prone to accidents. Like food and water, adequate sleep is essential to good health and quality of life. There are two types of sleep: non-rapid eye movement -- or NREM sleep -- and rapid eye movement -- or REM sleep. NREM sleep includes four stages, ranging from light to deep sleep. We cycle through these four stages of sleep approximately every 90 minutes. Then we go into REM sleep, the most active stage of sleep when dreaming often occurs. During REM sleep, the eyes move back and forth beneath the eyelids and muscles become immobile.
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