Yes, and the estimate is larger than most people expect. This is the part of the work-life conversation most often treated as soft advice, and it is not: there is a substantial body of work putting a number on it, and the threshold it identifies is 55 hours a week.
What do the figures actually say?
Joint estimates from WHO and the International Labour Organization found that "398 000 people died from stroke and 347 000 from heart disease as a result of having worked at least 55 hours a week" in 2016.
The underlying research, published in Environment International, puts the total at "An estimated 745,194 deaths" attributable to long working hours that year.
| Figure | |
|---|---|
| Threshold identified | At least 55 hours a week |
| Stroke deaths, 2016 | 398,000 |
| Heart disease deaths, 2016 | 347,000 |
| Estimated total | 745,194 |
How should you read those numbers?
Carefully, because they are easy to over-apply. This is a population-level estimate of attributable deaths, not a prediction about you specifically. It does not say that a 45-hour week is dangerous, and it does not say that a busy month will harm you.
What it does establish is that working hours are a genuine health variable rather than merely a lifestyle preference or a question of ambition. That reframing is the useful part. Hours are a thing to manage for health reasons, in the same category as sleep or activity, rather than purely a matter of personal tolerance.
Why 55 hours?
That is the threshold the analysis is anchored to. It is worth knowing your own real number rather than your assumed one, because the two often differ considerably once you count honestly.
Count everything: the hours you are formally paid for, the work done at home in the evening, the messages answered at the weekend, and the commute if you work during it. People routinely underestimate the total by several hours because the fragmented parts do not feel like work sessions.
Is this only about hours?
No, and hours are the easiest thing to measure rather than the only thing that matters. Research on recovery suggests that whether you mentally disengage during your non-work time is independently associated with outcomes. A meta-analysis of 91 samples found psychological detachment associated with lower exhaustion, higher life satisfaction, higher wellbeing and better sleep.
So an evening spent half-monitoring a work channel is not equivalent to an evening genuinely away from it, even though both look identical on a timesheet. Our article on why switching off matters covers that evidence.
Is any of this the employer's problem?
Materially, yes. WHO's guidance on mental health at work notes that "Globally, an estimated 12 billion working days are lost every year to depression and anxiety at a cost of US$ 1 trillion per year in lost productivity."
Workload, staffing and expectations about after-hours contact are organisational design choices. Personal boundaries help, but they are not a substitute for a job that can be done in the hours it is paid for, and the figures above make that a reasonable thing to raise rather than a soft complaint.
What to actually do
- Measure two ordinary weeks. Everything, including fragments. You cannot manage a number you have not counted.
- Compare it to 55. Not as a pass mark, but as the point the evidence is anchored to.
- Find where the overflow actually is. Usually one or two specific commitments rather than a general drift.
- Make one structural request. A change to scope, a deadline, or a recurring meeting is worth more than a private rule.
- Protect the disengagement, not just the clock. Turning off after-hours notifications does more than resolving to ignore them.
Worth raising with a clinician
Given that the risks identified here are cardiovascular, chest pain, breathlessness, or any symptom you associate with your heart is a reason to seek medical advice promptly rather than to reduce your hours and hope. Our complete guide to work-life balance covers the wider picture.
