Healthy Adults Need Less Sleep With Age

By Angela Young 16 months ago

A new study concludes that middle-aged adults are less likely than seniors and 20-year-olds to suffer from daytime sleepiness after not getting a good night's sleep. Because the need for nighttime sleep seems to decrease throughout one's lifetime, this information suggests that many people would benefit by simply adjusting the amount of time spent in bed as they age.

The small study followed three groups of healthy adults - young, middle aged, and older. The young group was made up of 20- to 30-year olds, the middle aged group was 40- to 55-year-olds and the older group was 66 to 83 year olds.

The groups, all of which were studied over a four night period, showed that slow wave sleep decreases and the number of nocturnal awakenings increases with age, according to Derk-Jan Dijk, PhD from the Surrey Sleep Center at the University of Surrey in England. His study's results appear in the Feb 1 issue of Sleep.

The authors of the article wrote that while eight hours rich in slow wave sleep may not be sufficient for young adults, it could be argued, based on their observation, that eight hours with less slow wave sleep is adequate for older healthy adults.

The researchers studied 44 young adults, 35 middle aged adults and 31 older adults. All of the participants were baseline healthy and underwent an initial 8-hour nocturnal sleep episode assessment. Next the participants were randomly subjected to two nights of either sleep without disruption or selective short wave sleep interruption by an acoustic stimuli, followed by a single night of recovery sleep.

Objective and subjective sleep propensity were assessed for this study using the Karolinska Sleepiness Scale (KSS) and Multiple Sleep Latency Test (MSLT) both standardized sleep measurement tools.

The researchers linked the total reduction in sleep time to an increase in the amount of awakenings and the subsequent duration of being awake after initial sleep onset. Previously, it was thought that difference was explained by the increase in latency to sleep onset.

The tests looked at subjective sleep propensity to conclude that the middle-aged group used was significantly less sleepy than the younger group and the older group fell somewhere in the middle of the two.

No matter the age, all three groups exhibited signs of increased sleepiness throughout the day following a night of continual disruption of slow wave sleep. The difference is that when the participants all had a solid eight hours of deep sleep time, only the younger group remained drowsy throughout the following day.

The authors do note that while there seems to be less daytime sleepiness amongst the two older groups tested, the sleep propensity was only measured during daylight hours and this difference thought to be age-related may disappear come nightfall.

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