Night shift fatigue
Night shift fatigue is driven largely by circadian disruption: working when the body is biologically primed for sleep, then attempting to rest during daylight hours when sleep is harder to obtain.
Night shifts are common in healthcare, logistics, rail, aviation, and security. The safety implications depend on task demand, duration, frequency, and recovery provisions.
Why night shifts are different
Section titled “Why night shifts are different”Compared with day work, night shifts often involve:
- Lower alertness and slower reaction times — particularly in the early hours
- Reduced sleep quality during daytime recovery
- Social and family disruption affecting long-term wellbeing
- Greater reliance on caffeine, lighting, and task rotation to maintain performance
These factors should be explicitly addressed in fatigue risk assessment, not assumed to be covered by generic working time rules alone.
Practical controls
Section titled “Practical controls”Controls that organisations commonly consider:
- Limit consecutive nights — cap blocks of night shifts where operationally feasible
- Recovery after nights — allow adequate rest before returning to day work
- Avoid quick returns — sufficient gap between a night shift and the next duty
- Task scheduling — place demanding tasks earlier in the shift where possible
- Lighting and environment — support alertness during low-circadian periods
- Education — help workers manage sleep hygiene around night work
Quantitative tools such as a fatigue risk index (FRI) may support roster review but should be interpreted by competent persons.
Related pages
Section titled “Related pages”Further research
Section titled “Further research”Peer-reviewed evidence on night shift performance and sector-specific night work standards will be incorporated in a future revision.