Physical activity partly inhibits autonomic imbalance, immune dysfunction and quality of life induced by chronic...

Chronic shiftwork can impair autonomic cardiovascular regulation and immune homeostasis. However, the interaction between occupational status and physical activity level in military police officers remains incompletely understood. This cross-sectional factorial study included 102 men stratified according to occupational status and physical activity level: physically active military police officers (PMP; n = 26), physically inactive military police officers (PMNP; n = 26), physically active civilians (CVP; n = 25) and physically inactive civilians (CVNP; n = 25). Quality of life, perceived stress, sleepiness, haematological parameters, cytokines and heart rate variability were assessed. Physical activity improved several Short-form questionnaire (SF-36) domains, particularly Physical Functioning and General Health. Military police officers demonstrated lower mean normal-to-normal intervals and lower high-frequency power than civilians, indicating differences in resting autonomic cardiovascular modulation associated with occupational status. Serum interleukin-10 concentrations were significantly lower in military police officers, whereas interleukin-2, interleukin-17 and interferon-γ did not differ significantly according to occupational status. Haemoglobin levels and platelet counts demonstrated significant occupational status × physical activity interactions. Perceived stress scores were lower in military police officers than in civilians. Chronic occupational exposure to shiftwork was associated with altered autonomic cardiovascular regulation and immune regulation in military police officers. Regular physical activity improved quality of life somewhat; however, several physiological alterations remained predominantly associated with occupational status, reinforcing the importance of occupational strategies targeting circadian health and physiological resilience. These findings highlight the physiological complexity of chronic shiftwork exposure in tactical occupational populations.