The heart of being overworked

Clinical Brief – August 1st

The Brief

A study found that working over 55 hours /week is tied to a significant increase in the risk of A-Fib – a quivering or irregular heartbeat that can lead to blood clots, stroke, heart failure and other heart-related complications.


Between 1991-2004, researchers recruited over 85,000 people in eight mainly European cohorts. Participants were on average 43 years old with women outnumbering men 2 to 1. A majority were from Finland.

Over an average of 10 years, about 1,000 cases of A-Fib were diagnosed:

  • Most people diagnosed were young: 71% happened before the age of 65
  • Most had no pre-existing conditions: 87% had no history of heart and vascular disease during the study

The risk of A-Fib was 1.4-fold higher for those who worked 55+ hours per week vs those who worked a standard 35- to 40-hour week.

This number didn’t change much even after other factors were ruled out by adjustment or exclusion, such as pre-existing heart and vascular conditions, age, sex, socioeconomic status, lifestyle factors, etc.

What does this mean?

Remember those headlines from a while ago about how doctors work awful hours? And it’s not just doctors, nurses work long hours too.

This study suggests some potential negative side effects of such work hours. Of course, it’s only an observation, so we still can’t say for sure that overwork can cause heart diseases like A-Fib.

On the other hand, a study published in JAMA last year showed a similar trend. In that study, nurses who worked more rotating night shifts had significantly higher risk of heart disease. Their results also suggested that the risk goes back down after the nurses stop doing shift work.

Bottom line

It’s nearly impossible to avoid those 55+ hour work weeks. But when we have to, watch for irregular heartbeats as a sign that it may be time to scale back, if only for period at a time.

2 thoughts on “The heart of being overworked

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