Serious heart attacks are more likely to occur at the start of a working week, a new study has found.

Researchers from Ireland's Belfast Health and Social Care Trust and the Royal College of Surgeons found that the chances of getting a severe form of heart attack, known as STEMI, on a Monday were 13% greater than on other days of the week.

STEMI or ST-elevation myocardial infarction is a serious heart attack that can likely result in serious complications or death. The life-threatening condition gets its name from the distinct pattern it creates on an electrocardiogram.

The condition occurs when one of the coronary arteries becomes completely blocked, causing the stoppage of oxygen-rich blood supply to a section of the heart. It requires immediate percutaneous coronary intervention (PCI), also called coronary angioplasty.

The researchers evaluated data from 10,528 patients admitted to hospitals with STEMI between 2013 and 2018. They found that heart attacks spiked at the start of a working week and the rate was highest on a Monday.

"We've found a strong statistical correlation between the start of the working week and the incidence of STEMI. This has been described before but remains a curiosity," Dr. Jack Laffan, who led the research at the Belfast Health and Social Care Trust, said in a news release.

Although the exact mechanism behind the "Blue Monday" phenomenon remains unclear, scientists believe it is linked to the circadian rhythm connected to the body's sleep or wake cycle.

"The cause is likely multifactorial, however, based on what we know from previous studies, it is reasonable to presume a circadian element," Laffan added.

"Someone is admitted to hospital due to a life-threatening heart attack every five it's vital research continues to shed light on how and why heart attacks happen. This study adds to evidence around the timing of particularly serious heart attacks, but 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 the future," said Prof. Nilesh Samani, medical director at the British Heart Foundation (BHF).

Heart Attack
A person experiencing chest pain. Pexels