A new study suggests that healthy older adults without sleep disorders may have a reduced "sleep need." The results were published in the Feb. 1 issue of the journal Sleep.
The U.K. study involved 110 healthy adults. They had no sleep disorders or sleep complaints. Their sleep was evaluated during an overnight sleep study.
Results show that total sleep time decreased with age. Older adults between 66 and 83 years of age slept about 20 minutes less than middle-aged adults and about 43 minutes less than young adults.
The study also found that the sleep of older adults was more fragmented and less intense. Awakenings during the night increased. And time spent in deep, slow-wave sleep decreased.
But it was younger adults who were sleepiest during the day. Older adults took longer to fall asleep during a daytime nap study.
"Our findings reaffirm the theory that it is not normal for older people to be sleepy during the daytime," lead author Derk-Jan Dijk, PhD, told the AASM. "If you are sleepy during the day you either don't get enough sleep or you may suffer from a sleep disorder."
In a 2008 study Dijk reported on the age-related reduction in the “maximal capacity for sleep.” Adults were allowed extended periods of sleep to determine their sleep need. The total daily sleep time of older adults (7.4 hours) ended up being 1.5 hours less than that of younger adults (8.9 hours).
It is unclear what may cause a change in the sleep need of older adults. The authors suggested that alterations in reproductive hormones or changes in the brain may be involved.
They added that the study did not address sleepiness during the evening hours. At that time of day older adults may be sleepier than young adults.
The authors also wrote that the results may help explain why some healthy older adults struggle with insomnia. They may be unaware of their reduced sleep need.
So insomnia may occur because they spend too much time in bed. “Sleep restriction” may help get their sleep back on track. This is one form of cognitive-behavioral therapy.
But it is important to note that many older adults have insomnia due to a medical condition. And they may have insomnia as a side effect of a medication.
Read more about sleep and older adults.
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