In developed countries people turn their clocks forward in spring and backwards in autumn. Forward-turning in spring means an hour is “lost” which usually means an hour less sleep and this reduction can be stressful until people's physiology adjusts. But can losing one hour of rest have a real effect? It seems so if the incidence of myocardial infarcts is anything to go by.
Janszky & Ljung from Sweden (NEJM 2008;359:1966-8) showed that coronary events are more common when people are deprived of their extra hour when they turn their clocks forward. Hospital admissions for infarcts rose significantly across the land, especially 2 days after change-over, compared to 2 weeks earlier or 2 weeks later. The effect was consistent over many years and most pronounced in people younger than 65 years old.
As if to prove the point, the opposite effect was found in autumn when the Swedes had fewer than average heart attacks immediately after the “extra hour” was added. The work suggests there are subtle relationships between sleep patterns, stress and cardiac events.
