‘Five hours of sleep enough for women to live longer’

Last Updated: Oct 02, 2010, 00:00 AM IST

London: Women who manage to get between five
and six-and-a-half hours of sleep every night are more likely
to live longer, a new study has claimed.

Researchers at the San Diego School of Medicine found
that women those who slept for between five and six-and-a-half
hours a night had the longest survival rates.

While adults are advised to sleep for seven to nine hours
every day to stay healthy, the researchers found that those
who get slightly less than the recommended amount tend to
outlive those who sleep much more.

The findings, they said, would help dismiss the long-held
belief that people aren`t getting enough sleep, the Daily Mail
reported.

The scientists, who monitored 459 elderly women in San
Diego for 14 years (since 1995) to try and establish a link
between sleep and mortality, found that those who slept for
between five and six-and-a-half hours daily had the longest
survival rates.

In their first study they worked out peoples` sleeping
habits using wrist activity monitors, which are able to tell
whether a person is awake or asleep by how much they move and
then count up the overall hours of sleep a night.

Last year the researchers tried to get back in touch with
all the women 14 years later to find out whether they were
still alive.

They established that those who had more than six and a
half hours sleep a night or less than five were far less
likely to be alive today.

Professor Daniel Kripke, who led the study, said: "The
surprise was that when sleep was measured objectively, the
best survival was observed among women who slept 5 to 6.5
hours.

"Women who slept less than five hours a night or more
than 6.5 hours were less likely to be alive at the 14-year
follow-up."

Professor Kripke said their study should allay some
people`s fears that they`re not getting enough sleep.

He added: "This means that women who sleep as little as
five to six-and-a-half hours have nothing to worry about since
that amount of sleep is evidently consistent with excellent
survival. That is actually about the average measured sleep
duration for San Diego women."

Long term studies show that those who drop down to five
hours or fewer face a 70 per cent extra risk of dying from all
causes.

The new study is published in journal Sleep.

PTI