Stages of Sleep

Our need for sleep is relatively constant over our lifetime but our ability to sleep well decreases. Older adults have a different sleep cycle than those who are younger. A normal sleep pattern follows a relatively predictable pattern that involves alternating periods of REM (rapid-eye-movement) and non-REM sleep (stages 1 to 4). Typically we drift off to sleep in non-REM sleep and progress into deeper sleep by moving from stage one through stage four. Non-REM sleep is accompanied by declines in heart rate, respiration, and blood pressure. Delta sleep (stages 3 and 4) provides our deepest and most restorative sleep. The REM stage of sleep is where dreaming occurs and is a more active stage of sleep in which your heart rate, blood pressure and breathing patterns are similar to being awake.

As we age, the percentage of time spent in REM sleep remains relatively stable although the first period of REM sleep comes faster and lasts for less time. The sleep of older adults is more fragmented with periods of wakefullness and less time is spent in deep, dreamless sleep. In particular, the amount of sleep in stage IV may be much less or absent in older adults. Older adults spend less time in stage 3 sleep and there may be an absence of stage 4 sleep.

Summary of Age-related Changes in Sleep

• Total sleep time decreases until age 80 and then increases slightly.
• Time in bed increases after age 65.
• Sleep is lighter (more stage 1, less stage 4).
• Onset to sleep lengthens, particularly for women.
• Awakenings are more frequent.
• Naps become more common.
• Frequency of respiratory disorders such as sleep apnea increase.
• Frequency of leg movements during sleep increases.