London, Feb 1 (Inditop.com) Healthy adults can manage with reduced sleep as they age and also feel less drowsy than their younger counterparts rebutting the concept that it’s normal for older people to feel drowsy during the day, a study has revealed.
Results show that during eight hours in bed, total sleep time decreased significantly and progressively with age.
Older adults slept about 20 minutes less than middle-aged adults, who slept 23 minutes less than young adults.
“Our findings reaffirm the theory that it is not normal for older people to be sleepy during the daytime,” said principal investigator Derk-Jan Dijk, professor of sleep and physiology at the University of Surrey, Britain.
“Whether you are young or old, if you are sleepy during the day you either don’t get enough sleep or you may suffer from a sleep disorder,” added Dijk.
The number of awakenings and the amount of time spent awake after initial sleep onset increased significantly with age, and the amount of time spent in deep, slow-wave sleep decreased across age groups.
Yet even with these decreases in sleep time, intensity and continuity, older adults displayed less subjective and objective daytime sleep propensity than younger adults.
Furthermore, two additional nights involving experimental disruption of slow-wave sleep led to a similar response in all age groups.
Daytime sleep propensity increased, and slow-wave sleep rebounded during a night of recovery sleep, said a Surrey release.
According to the study authors, this suggests that the lack of increased daytime sleepiness in the presence of an age-related deterioration in sleep quality cannot be attributed to unresponsiveness to variations in homeostatic sleep pressure.
The study was conducted at the Clinical Research Centre of the University of Surrey and involved 110 healthy adults without sleep disorders or sleep complaints — of them 44 were young (20 to 30 years), 35 were middle-aged (40 to 55 years) and 31 were older adults (66 to 83 years).
