Overwork shows up in working hours before it shows up in resignations: days that keep getting longer, work late at night and at weekends, leave that is never taken and breaks that disappear. The World Health Organization and the International Labour Organization link working 55 or more hours a week with a 35% higher risk of stroke than working 35 to 40 hours. Time data lets a manager see the pattern early and act on the workload.
Key takeaways
- Long hours carry a measured health risk, with 55 hours a week as the studied threshold.
- Burn-out is defined by the WHO as the result of chronic workplace stress that is not managed.
- The signs are patterns over weeks, not one late night.
- The remedy is to change the workload. Telling people to rest does not work on its own.
What does the evidence say about long hours?
In 2021 the WHO and the ILO published the first global estimates of the health cost of long working hours.
- 745,000
deaths from stroke and ischemic heart disease in 2016 linked to long working hours, 29% more than in 2000
WHO and ILO, 2021 - 35%
higher risk of stroke for people working 55 or more hours a week, compared with 35 to 40
WHO and ILO, 2021 - 17%
higher risk of dying from ischemic heart disease, for the same comparison
WHO and ILO, 2021
The study compared people working 55 or more hours a week with people working 35 to 40.
What is burn-out?
The WHO's International Classification of Diseases describes burn-out as an occupational phenomenon. It is not classified as a medical condition. The definition is a syndrome resulting from chronic workplace stress that has not been successfully managed, with three dimensions:
- feelings of energy depletion or exhaustion
- increased mental distance from the job, or feelings of negativism or cynicism about it
- reduced professional efficacy
The words "not successfully managed" matter. They put the cause in how work is organized, which is something a manager can change.
How far has the working day spread?
Microsoft's analysis of workplace activity up to February 2025 describes a day with no clear end.
- 29%
of active workers are back in their inbox by 10 pm
Microsoft, 2025 - 58
messages sent or received outside core hours by the average worker
Microsoft, 2025 - 16%
rise in meetings that start after 8 pm, year over year
Microsoft, 2025
Nearly one in five of the employees who work at weekends are checking email before noon on Saturday and Sunday.
What are the warning signs in time data?
Eight patterns to watch over four weeks or more
- Weekly hours above 50, week after week
- Days that end later each week
- Regular work after 10 pm
- Work on most weekends
- No leave taken in six months
- Breaks and lunch pauses that have stopped appearing
- One person logging time to many projects at once
- The schedule extended almost every day
Any one of these in a single week is ordinary. Several together for a month is a workload problem.
Who is at risk?
The reliable one
Extra work flows to whoever always says yes.
The only expert
Nobody else can cover, so they never switch off.
The new manager
Still doing the old job on top of the new one.
The remote worker
No commute marks the end of the day.
What should a manager do?
Check the pattern
Look at four to six weeks of hours, not one bad week.
Talk in private
Describe what you see and ask what is driving it. Do not open with a diagnosis.
Find the cause
Too much work, unclear priorities, a skills gap or a staffing gap.
Change the workload
Move work, extend a deadline or drop something. Advice to "take it easy" changes nothing.
Protect the boundary
Agree an end to the day and stop sending requests after it.
Follow up
Look at the hours again in two weeks.
Do
- Treat long hours as a planning failure to fix
- Make sure leave is taken
- Pay overtime that is owed
- Watch teams, then individuals
Do not
- Praise the person who is always online
- Send messages late and expect answers
- Use hours data to ask for more
- Assume silence means things are fine
For hourly staff, long hours are a pay matter too. See how to calculate overtime.
How does BirdsEye help you see overwork?
BirdsEye is a time tracker, not a health tool. What it gives you is an accurate picture of when work happens.
- A boundary by default. Tracking stops at the end of the working hours you set.
- Extensions you can see. On the Team plan and above, you can let people extend their own tracking by one hour, four hours or until the end of the day. Someone who extends every day is telling you something.
- Hours by day of week and by hour. The heat map shows late evenings and weekends plainly.
- Started and ended today. When each person's day began and finished.
- Leave records. Who has taken time off, and who has not.
- Time by project. Who is spread across too many things.
Employees see their own data, so the conversation can start from a shared picture. See reports and analytics.
Frequently asked questions
How many hours a week is overwork?
There is no single line. The WHO and ILO study found higher health risks at 55 or more hours a week, compared with 35 to 40. Sustained weeks above 50 hours are worth a conversation.
What are the first signs of overwork?
Days that get longer, work in the evenings and at weekends, skipped breaks and untaken leave. These appear in time records weeks before performance or attendance changes.
Is burn-out a medical condition?
The WHO classifies it as an occupational phenomenon, not a medical condition. It describes a syndrome that results from chronic workplace stress that has not been successfully managed.
Can time tracking prevent burnout?
It can make overwork visible early. Preventing it takes a manager who changes the workload once the pattern is clear.