The common belief that older people need less sleep has been debunked by a sleep and memory expert who said that older adults need as much sleep as the younger ones.
According to Prof Sean Drummond, sleeping less could lead to a decline in memory.
Prof Drummond said because the older people found it difficult to sleep it was assumed they needed lesser sleep, which was not true and could damage their health and brain ability.
He said catching the same amount of sleep when a person was 35 could help to keep away age related "cognitive decline" and improve general health.
"The ability to sleep goes down as you age but it is a myth that older people need less sleep," the Telegraph quoted Prof Drummond as saying at the American Association for the Advancement of Science.
The University of California psychologist went on: "Older adults benefit from getting as much sleep as they get when they were in their 30s. This varies from person to person but whatever you slept when you were 35 should be the same from 75.
"The problem is people find it harder to sleep as they get older and they think that that is a sign that they need less sleep but that is not the case.
"The quality of sleep may go down but they must maintain the quantity. This will have relevance to age related cognitive decline."
Prof Drummond conducted a test on 33 older adults, averaging 68 years of age, and found that insufficient sleep severely affected the brain.
The study showed that the less sleep the volunteers, the less likely they were to memorise a list of unrelated nouns.
Prof Drummond said: "People think that they can survive on less sleep but cognitive tests say otherwise. Seven to eight hours seems to be the optimal for longevity.
"Less than six hours has the effect of reducing their ability to carry out tasks and remember things.
He added: "Getting older adults to get back to the sleep they had when they were younger could be very useful in reducing cognitive decline." (ANI)