Heart Attacks More Likely on the Day You Might Suspect

Researchers have found yet another reason to dislike Mondays: Serious heart attacks are more likely to occur on this day, according to evidence presented recently at the British Cardiovascular Society conference. Doctors from the Belfast Health and Social Care Trust and the Royal College of Surgeons in Ireland analyzed data from 10,528 patients in Ireland and Northern Ireland who were admitted to the hospital between 2013 and 2018 with an ST-segment elevation myocardial infarction, also known as STEMI. According to the Cleveland Clinic, this type of heart attack involves a total blockage of one of the heart's main supply arteries. Between 2.5% and 10% of STEMI patients die within 30 days.

In looking at the days of the week in which the patients were admitted, researchers "found a strong statistical correlation between the start of the working week and the incidence of STEMI," cardiologist Jack Laffan says, per Science Alert. More than 1,650 patients showed up at the hospital on a Monday, which worked out to a 13% greater risk of this type of severe heart attack occurring on that day of the week. STEMI admissions were also above average on Sundays, though "not enough above to be statistically significant," according to Science Alert, which suggests "the added stress of going back to work after the weekend" is involved. Though the study didn't explore the possible reasons for the findings, Laffan says "it is reasonable to presume a circadian element" based on prior research.

According to Harvard Health, "when people’s behavior or environment is out of sync with their internal clock, it's known as circadian misalignment" and "this phenomenon may explain why heart attack rates rise on Monday mornings and the week after daylight savings time begins." A 2017 study of more than 156,000 patients in Sweden also showed a greater incidence of heart attacks on Mondays, with the authors suggesting added stress was a factor. British Heart Foundation medical director Nilesh Samani is now calling for research exploring "what it is about certain days of the week" that make severe heart attacks more likely. "Doing so could help doctors better understand this deadly condition so we can save more lives in future," Samani says. (More heart attack stories.)