A study, carried out by the Individual-Participant-Data Meta-analysis in Working Populations (IPD-Work) Consortium, pooled data from eight studies across Western Europe involving more than 85,000 adults and found people who work 55 or more hours a week had an increased risk of developing a type of irregular heartbeat known as atrial fibrillation.
Researchers analysed and adjusted for confounding factors such as respiratory infections, inflammatory conditions, diabetes, high blood pressure, stroke, and various forms of heart disease, who didn't have a diagnosis of AF at the start of the study between 1991 and 2004, had about a 40% increased risk of developing atrial fibrillation over 10 years.
Risk factors for AF assessed at the start of the study and during follow-up, included general confounders at baseline, including: age, gender, socioeconomic status, body mass index, smoking history, alcohol use and physical activity levels.
However, the number of people who developed AF during this study was small: only 1.24% and, even if working more than 55 hours a week does increase your risk of AF by around 40%, it would only be increasing it to something like 1.74% – which is still very small.
Although these findings on working hours are interesting, there are far more well-established lifestyle risk factors for heart disease, such as smoking, alcohol, diet, and physical activity levels.
Regularly working long hours could cause you physical and mental stress so it's important to get a good work-life balance. The best way to reduce your risk of heart and vascular problems is to have a healthy, balanced diet, take regular exercise, and avoid smoking and drinking too much alcohol.