How Many Work Hours Is Too Many? What WHO Found About 55-Hour Weeks

Working 55 or more hours a week is the level the World Health Organization (WHO) and the International Labour Organization (ILO) linked to a higher risk of stroke and fatal heart disease, compared with 35 to 40 hours. When your office is also your home, the workday has no natural end, and evening email and weekend catch-up can push a week toward that threshold without any single long day.

1. What the WHO and ILO study found

In May 2021, WHO and the ILO published their first global analysis of deaths and illness linked to long working hours, defined as 55 or more hours a week. The peer-reviewed study appeared in the journal Environment International, and WHO summarized the findings in a news release.

The headline numbers, for the year 2016:

• 745,000 deaths from stroke and ischemic heart disease were attributed to working at least 55 hours a week.
• That total was made up of 398,000 deaths from stroke and 347,000 from heart disease.
• The total represented a 29 percent increase since 2000.
• Deaths from heart disease linked to long hours rose 42 percent between 2000 and 2016, and deaths from stroke rose 19 percent.

The study itself reports that 488 million people, or 8.9 percent of the global population, were exposed to long working hours in 2016.

2. How big is the risk?

WHO's release states that working 55 or more hours a week is associated with an estimated 35 percent higher risk of a stroke and a 17 percent higher risk of dying from ischemic heart disease, compared with working 35 to 40 hours a week.

WHO describes long working hours as responsible for about one-third of the estimated total work-related burden of disease, making it the occupational risk factor with the largest disease burden in its analysis.

The burden was not spread evenly. According to WHO, 72 percent of the deaths were among men, and most deaths were among people aged 60 to 79 who had worked 55 or more hours a week between the ages of 45 and 74. The study counts deaths among older people who had worked long hours years earlier, so the harm it describes is cumulative, not immediate.

3. Why WHO mentioned teleworking

The release was published during the COVID-19 pandemic, and WHO's Director-General, Dr Tedros Adhanom Ghebreyesus, addressed remote work directly. He said teleworking had become the norm in many industries, "often blurring the boundaries between home and work," and that people still on payrolls were ending up working longer hours. He added: "No job is worth the risk of stroke or heart disease."

This is not a finding that remote workers specifically work more. It is a warning that the conditions of remote work can make long hours easier to slip into without noticing.

4. How a remote week drifts toward 55 hours

Here is an illustration with assumed numbers. A standard schedule of 8 hours a day, 5 days a week, is 40 hours, at the top of the 35-to-40-hour comparison range WHO used.

None of these pieces feels like a 55-hour week on its own. Together, they reach the threshold in the study. Spread across a five-day week, 55 hours is 11 hours a day.

5. How to check your own hours

1. Track one ordinary week honestly. Include message checks, weekend tasks and working lunches, not just scheduled hours. A simple note on your phone is enough.
2. Compare against two numbers: 35 to 40 hours, the standard range used in the study, and 55 hours, the long-hours threshold.
3. Look for the biggest add-on. In most weeks, one habit, such as evening email, accounts for most of the drift.
4. Set an end-of-day signal. Close the laptop, log out of chat, or move work apps off your phone's home screen.
5. Talk about workload, not just hours. If the work cannot fit in a standard week, that is a staffing or priority conversation with your manager.

6. What WHO says employers and governments can do

WHO's release lists three actions: governments can enforce laws that ban mandatory overtime and set maximum limits on working time; agreements between employers and workers can make working time more flexible while agreeing on a maximum number of hours; and employees could share working hours so that hours do not climb to 55 or more a week.

7. Key takeaways

• WHO and the ILO define long working hours as 55 or more a week.
• In 2016, long hours were linked to 745,000 deaths from stroke and heart disease, a 29 percent rise since 2000.
• Working 55+ hours a week is associated with a 35 percent higher stroke risk and 17 percent higher risk of dying from ischemic heart disease, compared with 35 to 40 hours.
• WHO's Director-General warned that teleworking can blur the line between home and work.
• Small daily add-ons can turn a 40-hour week into 55 hours; tracking one real week shows where the time goes.