It is generally thought that older people tend to suffer poorer sleep than their younger counterparts, but researchers in a recent study reveal the opposite, that sleep quality appears to improve over a lifetime.

Researchers surveyed more than 155,877 random Americans and found that people in their 80s had the least complaints about sleep troubles and daytime tiredness, compared to younger age groups.

"This flies in the face of popular belief," said study author Dr. Michael Grandner of the Center for Sleep and Circadian Neurobiology at the University of Pennsylvania in Philadelphia in a statement. "These results force us to re-think what we know about sleep in older people – men and women."

Women reported more sleep disturbances and daytime fatigue than men, and reports of poor sleep were linked to health problems and depression. 

Sleep quality generally improves with age, expect for a brief increase in sleep problems in middle age, which is also more pronounced in women than in men.   

"These results suggest that the often-reported increase in sleep problems is a non-linear phenomenon, mediated by factors other than physiologic aging," wrote the study authors.

Grandner noted that older people may be sleeping worse but just felt better about it than younger people. 

"Even if sleep among older Americans is actually worse than in younger adults, feelings about it still improve with age," said Grandner.

However, he added that, given the latest results, older adults should not dismiss sleep problems as a natural part of aging. 

"Once you factor out things like illness and depression, older people should be reporting better sleep. If they're not, they need to talk to their doctor. They shouldn't just ignore it," Grandner said.

The findings are published in the March issue of Sleep.