Fatigue in wildland firefighting: relationships between sleep, shift characteristics, and cognitive function

Background Wildland firefighting requires exposure to long shifts and poor sleep, which may pose a risk to worker safety due to impaired cognitive function. Aims We investigated the associations between sleep, shift characteristics, and cognitive function in wildland firefighters. Methods We conducted a within-subject observational study with 25 wildland firefighters from the British Columbia Wildfire Service, Canada. Data were collected remotely during the 2021 and 2022 fire seasons. Wrist-worn actigraphy and the psychomotor vigilance task served as objective, mobile measures of sleep and cognitive function, respectively. Web-based surveys were used to collect shift information and subjective cognitive function. Linear mixed effects modeling was used to control for inter-individual differences and explore the influence of participant-factors. Key results Average sleep duration on fire suppression days was 6.7 h (s.d. 66 min), while average shift duration was 13.8 h (s.d. 108 min). Poor sleep and longer shift durations were both associated with reduced cognitive function across all metrics (P < 0.01; P < 0.001). Conclusion Firefighters are often exposed to poor sleep and long shifts, which are both associated with impaired cognitive function. Implications Our results highlight the need for fire agencies to consider fatigue-related cognitive impairment as an important factor for worker health and safety.