Research found that the severest type of heart attack is most likely to happen on a Monday.
A cardiologist who led the study suggested this could be down to the body's wake and sleep cycle.
Other research suggested bring-drinking and stress could be the reason for a Monday heart attack.
The research looked at 10,528 patients who had been admitted to hospitals in Ireland with a specific heart attack called an ST-segment elevation myocardial infarction between 2013 and 2018. It was presented at the British Cardiovascular Society conference in Manchester, UK, on Sunday, and hasn't been peer-reviewed.
A STEMI is the most serious kind of heart attack and happens when a major coronary artery is completely blocked.
Symptoms include chest pain, shortness of breath, nausea, stomach pain, heart palpitations, anxiety, sweating, and feeling dizzy, according to Cleveland Clinic, although women are less likely to experience chest pain.
The research found there was a spike in STEMI cases at the beginning of the working week, most commonly on Monday, as well as more than expected on a Sunday.
Monday heart attacks could be linked to our body's sleep cycle
Cardiologist Dr. Jack Laffan, who led the study at the Belfast Health and Social Care Trust, said the correlation between STEMI and the start of the working week had been described before in other research. Scientists aren't sure of the cause, and it's likely to be multifactorial, but it's reasonable to presume that the circadian rhythm — the body's sleep or wake cycle — plays a role, he said.
A review of existing evidence published in 2005 that also found cardiovascular events are more likely to occur on Mondays suggested binge drinking on the weekend could trigger heart problems on a Monday, although it wasn't proven.
Insider previously reported that stress about the upcoming work week felt on a Sunday could raise levels of the hormones adrenaline and cortisol in the body, which could increase blood pressure and clotting, raising the risk of heart attacks.
Previous research suggested that cardiac arrests are also more likely to happen on a Monday. A cardiac arrest is different from a heart attack. While the heart stops beating during a cardiac arrest and the patient falls unconscious, they can remain conscious during a heart attack and their heart will continue to beat.
However, one study from 2019 involving a Northwestern community in the US found cardiac arrests didn't peak on Mondays — the only trend was a lower number of cases on Sundays.
Commenting on the new STEMI research, professor Sir Nilesh Samani, medical director of the charity the British Heart Foundation, said: "We now need to unpick what it is about certain days of the week that makes them more likely. Doing so could help doctors better understand this deadly condition so we can save more lives in future."
Read the original article on Insider