Last reviewed 5 August 2021

Mike Sopp looks at the potential impact of long working hours.

In May 2021 the World Health Organization (WHO) and International Labour Organization (ILO) published findings from a study into the health risks of long working hours.

The study concluded that “working 55 or more hours per week is associated with an estimated 35% higher risk of a stroke and a 17% higher risk of dying from ischemic heart diseases, compared to working 35–40 hours per week”.

From a UK perspective, studies by the TUC suggest that “full-time employees in Britain worked an average of 42 hours a week in 2018, nearly two hours more than the EU average – equivalent to an extra two and a half weeks a year”.

Similarly, the Chartered Institute of Personnel and Development (CIPD) UK Working Life Survey found that “three in five workers say they work longer hours than they want and one in four say they overwork by 10 or more hours per week”.

In addition to the TUC/CIPD findings, research by University College London (UCL) found that “employees who work long hours have a higher risk of stroke than those working standard hours”.

Indeed, in their conclusions UCL researchers suggest that “more attention should be paid to the management of vascular risk factors in individuals who work long hours”.

Long working hours and risks

Increasingly, employers in the UK are beginning to recognise the benefits of a good work-life balance for their employees.

One of the key elements of this balance is the hours worked by employees. Long working hours prevent a good work-life balance. There is evidence to suggest that certain working groups in the UK are working long hours.

Research undertaken by the CIPD in 2021 found that nearly 25% of those surveyed worked 10 hours or more overtime every week and concluded that “over-work, stress and poor work-life balance are undermining attempts to improve job quality in the UK”.

Findings by the CIPD are supported by the TUC. A report by them from 2018 found that:

  • 3.3 million employees work over 48 hours a week

  • almost half-a-million work more than 60 hours

  • 1.4 million people still work on all seven days of the week.

It is also worth noting that evidence from the Office for National Statistics indicates that employees working from home have worked more unpaid hours than those in the office.

The key question often posed is whether there is evidence to link long working hours with health problems.

In May 2021, the WHO and the ILO published the findings of a study into the effects of long working hours. It concluded that “long working hours led to 745, 000 deaths from stroke and ischemic heart disease in 2016, a 29% increase since 2000”.

This work-related disease burden is particularly significant in men (72% of deaths occurred among males), people living in the Western Pacific and South-East Asia regions, and middle-aged or older workers.

Most of the deaths recorded were among people dying aged 60–79 years, who had worked for 55 hours or more per week between the ages of 45 and 74 years. Of interest, the Japanese call this “karōshi”, which can be translated literally as "death from overwork" with the major medical causes of karōshi being deaths due to heart attack or strokes.

The findings of the WHO/ILO study support those of an earlier study by University College London published in 2014 on the link between coronary heart disease, strokes and long working hours.

Having analysed data from 25 previous reports, researchers concluded that people who work for more than 55 hours a week increase their risk of stroke by 33% compared to those who work a 40-hour week. The 55-hours-plus workers also increased their risk of coronary heart disease by 13%.

However, working long hours also has potential safety issues. The CIPD report above also concluded that “it is clear that the working of long hours is contributing to mistakes across all occupations and, for certain professions, this can result in potentially fatal consequences either for the workers themselves or for other people”.

The main physical effect of excessive hours of work is tiredness and fatigue, which in turn may lead to an inability to concentrate, or carry out heavy or strenuous physical work, or work at a pre-determined rate, thereby leading to potential unwanted events and consequent decreases in productivity as a result.

It is worth noting that the CIPD has urged “employers to fulfil their statutory duty of carrying out a comprehensive health and safety risk assessment”.

Employer duties

There is a general duty on every employer, under s.2(1) of the Health and Safety at Work, etc Act 1974, to ensure so far as is reasonably practicable the safety, health and welfare of all employees.

This implies a restriction on the employment of any employee for excessively long hours likely to cause physical or mental ill health, or precipitate fatigue-induced accidents. In respect of the qualification of the general duty by the words “so far as is reasonably practicable”, it should be noted that the burden of proving that hours were not excessive would fall upon the employer.

However, it should also be borne in mind that employees also have a duty to take reasonable care of their own health and safety and that of other people, who may be affected by their activities at work. This duty implies that employees should take positive steps to understand the risk factors in their work, such as the causes of fatigue, comply with safety rules and procedures and make sure that nothing they do or fail to do at work puts anyone at risk.

As well as the general duties contained within the Health and Safety at Work, etc Act 1974 applying to working hours, the Health and Safety Executive states that under the Management of Health and Safety at Work Regulations 1999, “employers are required to make an assessment of the risks to employees from work activities and make a commitment to introduce measures that are reasonably practicable to remove or control these risks. This includes the number of hours worked and how these hours are scheduled”.

Specific requirements concerning hours of work are contained in the Working Time Regulations 1998 (as amended) (WTR). These regulations contain a mixture of health and safety and employment law requirements including placing an average working limit of 48 hours a week over a 17-week period which a worker can be required to work. Other requirements include:

  • a limit of an average of 8 hours work in 24 which night workers can be required to work

  • a right for night workers to receive free health assessments

  • a right to 11 hours’ rest a day

  • a right to a day off each week.

Other more specific requirements are made in relation to young workers (those under 18 years of age). For example, young workers may not ordinarily work more than 8 hours a day or 40 hours a week, although there are certain permitted exceptions.

Many of the provisions of the WTR can be modified or excluded by a workforce agreement or a collective agreement. However, the WTR inserted new provisions into the Employment Rights Act 1996, which make it unlawful to subject any “worker” to any detriment because, among other matters they:

  • refuse to exceed any limit on working time set by the WTR

  • refuse to sign a workforce agreement or make any other agreement, such as an individual opt out from the average weekly working time limit

  • make an allegation in good faith that the employer has contravened a right under the WTR or brings proceedings under the WTR.

There are also other regulations that impose specific requirements on employers with regard to the number of hours worked and how these hours are scheduled. These include the Road Transport (Working Time) Regulations 2005 and the Railway and Other Guided Transport Systems (Safety) Regulations 2006. These Regulations include a duty to make arrangements to prevent serious consequences arising from tired/fatigued employees and so endanger safety.

Assessment and risk control

Clearly, employers need to assess the risks associated with long working hours, particularly as work environments and working practices change following the Covid pandemic.

For the employer, there is a clear balance to be drawn between allowing workers the freedom of working the hours that they desire (or need to work) and their responsibilities to these workers under health and safety legislation.

Identifying issues associated with long hours can be difficult because there are many contributory factors that may affect employees. It is advisable, to use a variety of information-gathering techniques to try to identify any common trends or patterns. Techniques that can be used to identify hazards include:

  • investigating employee complaints

  • examining accident and sickness records

  • conducting employee surveys

  • environmental and medical monitoring

  • assessing expert reports

  • reviewing scientific and medical literature

  • incident, injury and illness investigation.

Factors to consider when assessing the risks posed by the hazards of long hours include:

  • type of work activities being undertaken along with any plant and equipment being used

  • current workload of employees/organisational change that may impact on workloads

  • personal needs and work experience of employees

  • any special circumstances that may be on the site

  • current work patterns being adopted (eg flexible and home working)

  • impacts on other employees.

While excessive work hours have the potential to harm all employees, some workers may be at particular risk. These include:

  • younger or older workers

  • new and expectant mothers

  • workers with pre-existing health conditions

  • workers taking time-dependent medication (such as insulin)

  • workers who have secondary employment.

When undertaking the risk assessment process, it is very important to consult workers and/or their safety representatives as they have a clear interest in the matter and a direct knowledge of the advantages and disadvantages of existing work hours being undertaken.

Where an employee is working in excess of the 48-hour limit, the employer in its simplest form, has a number of options if they believe harm is likely, namely:

  • reducing the working hours (eg by changing contracts of employment)

  • entering into a written agreement with the individual worker to work more than the weekly limit but with strict controls and adequate health surveillance

  • negotiating a workforce or collective agreement to extend the 17-week reference period to take account of times when the business is less busy and working hours are less

  • introducing “flexible working” patterns based upon the needs of employer and employee.

One solution does not fit all and it may be a case of introducing longer-term solutions based upon a change in culture. Key is a strong business rationale and culture that recognises the potential impacts of long working hours. This should be combined with good leadership that sets an example to other employees.

As an example, an employer can use criteria which reward employees for innovation and the quality and quantity of work produced, rather than for the hours they put in.

Good awareness and information for employees on the health and safety risks and lifestyle choices that prevent strokes or heart attacks can also assist.

Employee involvement and engagement can also lead to resolving any issues associated with long working hours. For example, regular one-to-one meetings with employees to ask questions about workloads can help to identify people who are overloaded and may be struggling, ensuring that advice and support can be given as quickly as possible.

Further information

  • Global, Regional, and National Burdens of Ischemic Heart Disease and Stroke Attributable to Exposure to Long Working Hours for 194 Countries, 2000–2016: A Systematic Analysis from the WHO/ILO Joint Estimates of the Work-related Burden of Disease and Injury, Sciencedirect

  • CIPD Good Work Index, CIPD website

  • Long Hours resources, TUC

  • Working Long Hours (HSL/2003/02),