Sensorimotor network hyperactivity and impaired psychomotor performance associated with cumulative occupational...

Firefighters face chronic occupational stressors including trauma exposure, sleep disruption, and substantial physical demands that can compromise brain function and cognition. Despite increasing concern regarding stress-related cognitive decline in this population, limited evidence is available on whether occupational stress is associated with alterations in resting-state networks (RSNs) or whether such neural changes relate to cognitive outcomes. This study investigated occupational stress-related alterations in functional connectivity (FC) across major RSNs and examined their associations with cognitive performance in firefighters. Ninety-eight actively employed firefighters and 98 demographically matched non-firefighter controls underwent resting-state functional magnetic resonance imaging. RSN-specific FC was derived using independent component analysis. Group comparisons identified significantly higher FC within the sensorimotor network (SMN) in firefighters relative to controls (family-wise error-corrected P < 0.05). Within the firefighter group, both longer cumulative duration of emergency duties (β = 0.45, P = 0.013) and higher alcohol use levels (β = 0.37, P = 0.003) were independently associated with increased SMN connectivity. Moreover, SMN hyperconnectivity was significantly correlated with poorer psychomotor performance (β = -0.19, P = 0.023), indicating potential behavioral consequences. These findings provide evidence that chronic occupational stress and maladaptive coping behaviors such as alcohol misuse may contribute to functional reorganization of the SMN in firefighters which may be linked to diminished psychomotor efficiency. The results highlight a potential neurobiological mechanism through which occupational stress influences cognitive functioning and underscore the need for early identification of at-risk individuals and targeted interventions to mitigate cumulative stress burdens in this vulnerable occupational group.