January 13, 2009 – Sleep could help protect the arteries of the heart, indicate preliminary data from a US study published in the Journal of the American Medical Association (JAMA).
According to the results of the observational test1, the coronary arteries were more calcified in people who got little sleep than in those who got 7 hours or more of sleep per night.
Calcification, or arterial plaque formation, is associated with atherosclerosis (hardening of the arteries) which increases the risk of heart problems.
The clinical trial involved 495 subjects who had no arterial calcification at baseline, based on the results of a medical tomographic imaging test. After a five-year follow-up, a new tomographic examination revealed that 12.3% of them presented calcifications to varying degrees.
The incidence of arterial calcifications was approximately 9.5% in subjects who slept less than 4 hours per night. In comparison, it was 4% in subjects who slept 4 to 5 hours per night, about 2% when sleep lasted 5 to 7 hours, and almost non-existent in those who slept 8 hours or more.
It is not known by what mechanism sleep could protect against the formation of arterial plaques. Researchers believe that it’s possible that a good night’s sleep could help reduce stress levels, which are believed to be associated with calcifications. Sleep has been noted previously to lower blood pressure, which may provide respite for the arteries and reduce inflammatory processes that can lead to arterial plaque build-up.
Note that arterial calcifications are not currently considered a symptom of cardiovascular disorders. They are considered, at most, as a possible risk factor. The presence of the onset of calcification in the arteries does not systematically lead to coronary heart disease.
Further studies will need to be carried out to measure the precise effect of the number of hours of sleep on arterial calcifications and on cardiovascular disease.
Pierre Lefrançois – PasseportSanté.net
1. King CR, Knutson KL, et al. Short sleep duration and incident coronary artery calcification. JAMA. 2008 Dec 24; 300 (24): 2859-66.
