The health benefits of getting enough sleep

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Skimping on sleep linked to hardened

arteries

14:49 24 December 2008 by New Scientist and Reuters

***Just one extra hour of

sleep a day appears to lower the risk of developing calcium deposits in the

arteries, a precursor to heart disease, US researchers said on Tuesday. **The finding adds to a growing list of health

consequences - including weight gain, diabetes and high blood pressure - linked

to getting too little sleep.*****

" We found that people who on average slept longer were at reduced risk of

developing new coronary artery calcifications over five years, " said Diane

Lauderdale of the University of Chicago Medical Center, whose study appears in

the Journal of the American Medical Association.

" It was surprisingly strong, " Lauderdale said. Calcium deposits in

the coronary arteries are considered a precursor of future heart disease.

" It's a very early marker of

future risk, " she said.

Unlike other studies looking at the risks of getting too little sleep, which

use people's own estimates of their sleep patterns, Lauderdale's team set out

to measure actual sleep patterns.

They fitted 495 people aged 35 to 47 with sophisticated wrist bands that

tracked subtle body movements. Information from these recorders was fed into a

computer program that was able to detect actual sleep patterns.

The team used special computed tomography, or CT, scans to assess the buildup

of calcium inside heart arteries, performing one scan at the start of the study

and one five years later.

Seven hours

After accounting for other differences such as age, gender, race, education,

smoking and risk for sleep apnea, the team found sleep duration appeared to

play a significant role in the development of coronary artery calcification.

About 12% of the people in the study developed artery calcification during the

five-year study period.

Among those who had slept less than five hours a night, 27% had developed

artery calcification. That dropped to 11% among those who slept five to seven

hours, and to 6% among those who slept more than seven hours a night.

Lauderdale said it is not clear why this difference occurred in people who

slept less, but they had some theories. Because blood pressure tends to fall

off during sleep, it could be that people who slept longer had lower blood

pressure over a 24-hour period.

Stress hormone

Or, it could be related to reduced exposure to the stress hormone cortisol,

which is decreased during sleep.

Or it may be some unidentified process. " It's something of a

mystery, " Lauderdale said.

Kathy , a sleep researcher from the University

of Rochester's School

of Nursing in New York, said the study underscores the

role sleep plays in health.

*** " People think that sleep doesn't

matter, but clearly it does. Sleep

deprivation is a public health problem and studies such as this show how

increasing sleep duration can have tremendously positive effects, " ,

who was not involved in the research, said in a statement.***

***Lauderdale said her findings should be confirmed by others, but said many

studies point to the need for at least six hours of sleep a night.***