- Fatigue from shift and night work is a recognised health and safety risk that raises the chance of errors and accidents.
- Employers have duties under health and safety law and the Working Time Regulations 1998, including a free health assessment for night workers.
- Meeting the minimum legal hours limits is not enough on its own; fatigue must still be assessed and managed.
- Good rota design, and access to occupational health for night workers, reduce the risk.
Shift and night work keep essential services running, but they come at a cost to the body that employers have a duty to manage. Fatigue is not simply a matter of individuals feeling tired; it is a recognised health and safety risk that degrades concentration, judgement and reaction time, and raises the likelihood of errors and accidents, on the job and on the drive home.
What shift work does to the body
Human beings are built around a daily circadian rhythm that governs sleep, alertness and many bodily processes. Working against that rhythm, particularly at night, disrupts sleep and can, over time, contribute to a range of health effects, including gastrointestinal problems, cardiovascular and metabolic conditions, and effects on mental health. In the short term, the most immediate risk is impaired performance during the low-alertness window in the early hours of the morning.
Fatigue is largely created by how work is designed and scheduled, which means it is largely within the employer's control.
The employer's duties
Fatigue sits squarely within health and safety law. Under the Health and Safety at Work etc. Act 1974 and the Management of Health and Safety at Work Regulations 1999, employers must assess and control the risks from fatigue, and HSE guidance on managing shift work (HSG256) sets out how. The Working Time Regulations 1998 add specific limits: night workers should not work more than an average of eight hours in any 24, workers are entitled to minimum daily and weekly rest, and, importantly, employers must offer night workers a free health assessment.
Good practice
Meeting the legal hour limits is necessary but not sufficient. The HSE is explicit that complying with the Working Time Regulations alone does not discharge an employer's duty to manage fatigue; the pattern of work, not just its total, has to be assessed and controlled.
Managing the risk
Good rota design does much of the work. HSE guidance points to forward-rotating shifts, which move from mornings to afternoons to nights; limiting the number of consecutive night shifts; avoiding overly long shifts and excessive overtime; and scheduling safety-critical tasks away from the least alert parts of the night.
- Do shifts rotate forwards, and are consecutive night shifts limited?
- Are shift lengths, overtime and shift-swapping controlled and monitored?
- Are safety-critical tasks kept away from the early-hours low point where possible?
- Are rest breaks, and enough time to rest and recover between shifts, built in?
- Can workers report fatigue without blame, and is the risk reassessed when patterns change?
The health of night workers
The free health assessment for night workers is both a legal requirement and a practical opportunity. It helps identify workers for whom night work poses a particular risk, for example because of a health condition, and allows suitable adjustments, or where necessary a move to suitable daytime work, to be considered. Pregnant workers need particular attention, as night and long shifts carry specific risks.
Where occupational health fits
Occupational health provides the night-worker health assessments the Regulations require, and advises employers on managing the health risks of shift work. Where an individual is struggling with the effects of shift work, a management referral gives work-focused advice on fitness and adjustments. Managed well, shift work can be run in a way that protects both safety and the long-term health of the people who sustain it.
This article is general guidance for employers and is not individual medical or legal advice. If you are unsure how it applies to your organisation, contact our team.