Are heart attacks more dangerous in the morning?

28th April 2011

Research has shown that it may be significantly more dangerous to suffer a heart attack in the morning than later in the day.

Patients struck down by heart problems between 6am and noon are likely to suffer five times as much damage to their heart muscle as those who have a heart attack later in the day, a Spanish study showed.

Scientists at the National Centre of Cardiac Research in Madrid believe that the phenomenon can be attributed to natural changes in blood pressure, hormone levels and metabolic rates which occur when a person wakes up.

They studied 811 patients who were admitted to hospital following a heart attack over a six-year period. They gauged the severity of the attack by looking at enzymes and found that damage was 21 per cent more severe in the morning than later on.

Researchers discovered recently that heart attacks were most likely to happen in the morning, specifically between the hours of 4am and 10am. It has also been suggested that Monday is the most common day for a heart attack to occur.

By Edward Bartel

 1. Shea, Steven A. "Existence of an Endogenous Circadian Blood Pressure Rhythm in Humans That Peaks in the Evening". Circulation Research. April 2011-04-28
2. Suárez-Barrientos, Aida, "Circadian variations of infract size in acute myocardial infarction." Heart. 27th April 2011.

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