Firefighters’ occupational stress and its correlations with cardiorespiratory fitness, arterial stiffness, heart rate variability, and sleep quality

This study investigated the correlations between firefighters’ occupational stress and cardiorespiratory fitness, arterial stiffness, heart rate variability, and sleep quality. We examined 705 male firefighters aged 40–50 years in Seoul City, Korea from November 2016–December 2017. The Occupational stress scale was used to evaluate occupational stress; an exercise stress test was administered to measure participants’ maximal oxygen uptake (VO(2)max); brachial-ankle pulse wave velocity was used to measure firefighters’ arterial stiffness; their autonomic nervous system activities were analyzed to determine heart rate variability (HRR); and the Pittsburgh Sleep Quality Index was used to assess their sleep quality. We divided the sample population into tertile groups per their occupational stress scores; i.e., low-stress group (n = 233), medium-stress group (n = 237), and high-stress group (n = 235). They were compared per each indicator and correlations were examined. There was a significant difference in VO(2)max (p < .01), and arterial stiffness (p < .001) according to occupational stress levels. Occupational stress was significantly correlated with cardiorespiratory fitness (r = -.820, p < .05), arterial stiffness (r = .085, p < .05), and sleep quality (r = .276, p < .001), but not HRR. In conclusion, Firefighters’ occupational stress is a key factor behind their elevated risk of cardiovascular diseases; therefore, we recommend programs aimed at reducing their occupational stress and preventing cardiovascular diseases.