Health Discoveries in General Health News

Morning heart attacks may be more severe

May 3, 2011
A Spanish study found that the body's circadian clock may influence the severity of heart attacks and what time of day they are more likely to occur.

Published online in the journal Heart, the research team from the National Center for Cardiovascular Research in Madrid, Spain, found that when attacks occur from 6 a.m. to noon, they may damage as much as 20 percent more of the heart muscle than attacks experienced later in the day or nighttime.

An individual's circadian rhythm, or "body clock," may cause changes in the nervous system and cortisol levels and may release substances into the bloodstream that increase the risk of a heart attack.

"It is well-known for decades that the incidence of heart attack is variable across the time of the day," said the center's Dr. Borja Ibanez. "What was completely unexplored was the effect of the time of the day of onset of the heart attack on the extent of heart muscle death…[and] that the human heart has a variable tolerance to ischemia according to the time of the day."

Thomson Reuters ranks North Shore University Hospital in Manhasset, New York, among the top 100 hospitals for cardiovascular care. The hospital is part of the North Shore-LIJ Health System.
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