Adapting shift work schedules for sleep quality, sleep duration, and sleepiness in shift workers (Cochrane Review)
Summary
This Cochrane review analyzed 11 studies with more than 2,000 shift workers to see how schedule changes affect sleep and alertness. The results showed mixed and often uncertain effects. Forward-rotating schedules (day → evening → night) and faster rotations may reduce sleepiness during shifts, but the evidence is weak, and faster rotations also shortened total sleep time. The most clear finding came from studies limiting maximum shift length to 16 hours, which gave workers about 45 minutes more sleep per day and slightly reduced on-shift sleepiness. Other changes, like shorter shifts or compressed workweeks, showed no consistent benefits. Overall, scheduling tweaks can influence fatigue, but the evidence remains limited and more high-quality research is needed.
Why It Matters For Night Shift Workers and Night Owls
For people working nights, the biggest takeaway is that not all schedule changes are equal. Limiting very long shifts has the strongest evidence for helping workers feel less sleepy and get more rest. Forward or faster rotations might reduce drowsiness during a shift, but the trade-off can be less sleep off-shift. Because research results are uncertain, workers may need to combine smarter scheduling with personal sleep strategies to manage fatigue and stay safe on the job.
Notes
Lay summary: https://www.cochrane.org/evidence/CD010639