Getting 1 extra hour of sleep per night can translate into a 33% reduction in the development of coronary artery calcification, a subclinical predictor of coronary heart disease. Adding 1 extra hour of sleep per night produced a benefit equivalent to lowering systolic BP by 17 mm Hg, according to data from an ongoing study called Coronary Artery Risk Development in Young Adults.
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Research focused on 495 healthy adults ages 35 to 47 who had two electron-beam computed tomography scans 5 years apart to assess the accumulation of calcified plaques in their coronary arteries. They also logged their sleep hours and wore a wrist activity monitor for six nights to estimate actual sleep duration.
In all, 61 of the study participants (12%) developed coronary artery calcification during the 5 years of follow-up. Calcified arteries were detected in 27% of those who slept less than 5 hours per night, compared with 11% of those who slept 5 to 7 hours per night. In those sleeping more than 7 hours per night, only 6% developed coronary artery calcification. Benefits of sleep didn't vary by race, but women seemed to benefit more than men.
Researchers concluded that more sleep is associated with lower calcification incidence independent of such variables as age, race, sex, body mass index, BP, diabetes, education, smoking status, and depression.
Source: King CR, Knutson KL, Rathouz PJ, Sidney S, Liu K, Lauderdale DS. Short sleep duration and incident coronary artery calcification. JAMA. 2008;300(24):2859-2866.