Working 55 hours a week causes 745,000 deaths a year worldwide, says WHO

Watch: Long working hours a death risk, says WHO

Regularly working overtime to impress the boss or keep on top of your to-do list may not be a harmless habit.

Many UK employees have put in extra hours amid the pandemic, with overtime often an inevitable consequence of working from home.

A survey by LinkedIn and the Mental Health Foundation suggests the average Briton worked an additional 28 hours a month during the UK's first lockdown, with more than one in ten (12%) logging on before 7am and nearly one in five (18%) working into the evening.

A World Health Organization (WHO) study has now revealed people who work 55 hours a week or more are more likely to die of heart disease or a stroke than those who graft for 35 to 40 hours every seven days.

Read more: Shift workers more likely to catch coronavirus

In 2016 alone, more than 745,000 deaths worldwide were "attributable to this exposure" – a 29% increase since 2000.

Working long hours may trigger internal "stress" or prompt an employee to lead a less healthy lifestyle, by smoking, drinking excessively and being sedentary.

"The COVID-19 [the disease caused by the coronavirus] pandemic has significantly changed the way many people work,“ said Dr Tedros Adhanom Ghebreyesus, WHO's director-general.

"Teleworking has become the norm in many industries, often blurring the boundaries between home and work.

"In addition, many businesses have been forced to scale back or shut down operations to save money, and people who are still on the payroll end up working longer hours.

"No job is worth the risk of stroke or heart disease.

"Governments, employers and workers need to work together to agree on limits to protect the health of workers."

Read more: Healthy heart helps people solve problems

The LinkedIn-Mental Health Foundation survey found that a quarter (25%) of its two thousand respondents felt under pressure to "stay online" beyond the end of their shift.

At-home workers may be worst affected, with Office for National Statistics data revealing people who set up a remote office for any length of time in 2020 did six hours of unpaid overtime a week.

This is nearly double the 3.6 additional hours put in by those who never worked from home.

The Hours of Work (Industry) Convention states an employee's working hours should not exceed eight hours a day and 48 hours across the week, "with some exceptions".

The definition of long working hours varies according to each country, however, most consider 35 to 40 hours a week to be "standard", and anything that exceeds that "overtime".

Read more: Sleep for six to seven hours a night to maximise heart health

To learn more, scientists from the WHO and International Labour Organization estimated the "exposure" of long working hours in 194 countries.

The "attributable burdens" of heart disease and strokes was calculated for 183 of the countries in 2000, 2010 and 2016.

Results reveal that in 2016, 488 million people – 8.9% of the global population – worked for at least 55 hours a week. This equates to 11 hours a day across a five-day working week.

Around 398,000 stroke and 347,000 heart disease-related deaths, respectively, "were attributable to this exposure".

Overall, working long hours was found to have caused 3.7% and 6.9% of all heart disease and stroke-related deaths, respectively.

The risk was most pronounced in South-East Asia and the Western Pacific.

Nearly three-quarters (72%) of the deceased were men.

"People of middle to older working age" were also more at risk, with most dying between 60 and 79 years old after working for 55 hours or more a week between the ages of 45 and 74.

Watch: Heart disease higher among women with brittle bones

Between 2000 and 2016, the number of people "exposed" to longer working hours increased by 9.3%.

Over these 16 years, heart disease and stroke fatalities due to working long hours also rose by 41.5% and 19%, respectively.

Overall, the scientists have concluded working 55 or more hours a week raises a person's risk of dying from a stroke or heart disease by 35% and 17% respectively, compared to putting in just 35 to 40 hours.

"If this trend continues, it is likely the population exposed to this occupational risk factor will expand further," the scientists wrote in the journal Environment International.

The team has partially blamed this trend on the rise of "gig economies", when a temporary employee is hired for a short-term project.

"Past experience has shown working hours increased after previous economic recessions," wrote the scientists.

Therefore, "such increases may also be associated with the COVID-19 pandemic".

Working hours aside, heart disease and strokes are also said to be on the rise worldwide. In the UK alone, more than one in four deaths are cardiovascular-related.

"Working 55 hours or more per week is a serious health hazard," said Dr Maria Neira, director of the department of environment, climate change and health, at the WHO.

"It's time we all – governments, employers and employees – wake up to the fact long working hours can lead to premature death".