# Effects of a 24/48 to 48/96 Shift Schedule Change on Firefighter Sleep and Health: Short-Term Improvements and Six-Month Stability

## TL;DR

Changing firefighters' shift schedules from 24/48 to 48/96 improved sleep and mental health in the short term, with benefits lasting six months.

## Contribution

The study provides evidence that a 48/96 shift schedule improves firefighter sleep and psychological health compared to a 24/48 schedule.

## Key findings

- Firefighters experienced significant improvements in total sleep time and sleep efficiency after the shift schedule change.
- Psychological health indicators like insomnia and depression scores improved, while anxiety and fatigue remained stable.
- The positive effects of the new schedule were maintained for six months without further improvement.

## Abstract

This study examined the impact of a shift schedule change on firefighter sleep and health outcomes (n = 24). Firefighters from a U.S. department transitioned from a 24 h on, 48 h off (24/48) schedule to a 48 h on, 96 h off (48/96) schedule. Wrist actigraphy and self-reported health outcomes were assessed at three time points: baseline (24/48), 3 months post-transition, and 6 months post-transition. Objective sleep measures included total sleep time (TST), sleep efficiency (SE), sleep onset latency (SOL), and wake after sleep onset (WASO). Self-reported health outcomes included the Insomnia Severity Index (ISI), Beck Depression Inventory–II (BDI-II), Beck Anxiety Inventory (BAI), Multidimensional Assessment of Fatigue (MAF), and the Alcohol Use Disorders Identification Test (AUDIT). Linear mixed-effects models (LMMs) with random intercepts were used to evaluate changes over time, adjusting for age, years of service, and individual night-time call volume. Results showed significant improvements in TST, SE, SOL, and WASO at the 3-month follow-up, which were sustained but did not further increase at 6 months. ISI and BDI-II scores also improved, while BAI, MAF, and AUDIT remained stable. These findings suggest that the 48/96 schedule may provide short-term improvements in sleep and psychological health for firefighters in low call-volume settings. Additional research is needed in higher-volume departments and over longer timeframes.