Our looks are the the only thing that changes with age. Changes to our sleep patterns are also a normal part of the aging process.
Although most people think that you are supposed to sleep less when you hit your golden years, that is not necessarily the case.
Over a typical lifespan, the amount of time we spend each day sleeping declines. Newborns spend from 16 to 20 hours asleep. Between the ages of one and four, total daily sleep time decreases to about 11 or 12 hours. A rule of thumb is that by the time you hit 10 years of age, you should see be sleeping at least 10 hours. Adults through middle age need at least 7.5 hours, and although the elderly may still require up to eight hours, they may struggle to obtain those hours in one block.
Sleep, in fact, does change as people age; people frequently report more problems initiating sleep when compared to their younger self. But, what changes exactly? In order to answer this question completely, we must first understand how we sleep. Sleep occurs in stages throughout the night. Sleep is not merely an on or off switch. These stages are broken down into NREM sleep (stages 1,2,3) and REM sleep. These cycles occur 4-6 times a night and basically start with stage 1, then stage 2, then stage 3, then REM sleep. We cycle in and out of these stages in a regular pattern; usually every 90-120 minutes (as above).
It is a common thought that sleep length declines with age. In fact, time remains pretty stable throughout adulthood. We do see however changes in patterns of our sleep, also called sleep architecture. Studies on the sleep habits of older Americans show an increase in the time it takes to fall asleep (sleep latency), an overall decline in REM sleep, and an increase in sleep fragmentation (waking up during the night) with age.
Aging has a definite effect on sleep and sleep stages. As we age we tend to lose slow-wave, or restorative, sleep. This becomes most marked in older adulthood. REM, or dream sleep, reduces slightly with aging. Contrary to popular belief, REM sleep is not the most restorative or restful stage of sleep. Sleep overall becomes more fragmented and lighter as we age as well.
Even though we do change our sleep architecture, sleep length stays pretty constant though time. The elderly report more trouble initiating and maintaining sleep and in the long run to have less slow wave sleep which would account for that feeling of having non-restorative sleep.