Sex and physical fitness status differences in heart rate variability and cardiorespiratory indices during long-term exposure to particulate air pollution

Purpose: The current study investigated the impact of gender (men vs. women) and cardiovascular fitness status (active vs. sedentary) on heart rate variability (HRV) [standard deviation of NN intervals (SDNN), root mean square of successive RR interval differences (RMSSD), low-frequency (LF), high-frequency (HF)] following performing an exhaustive exercise in an air-polluted environment. In addition, we measured the impact of gender (men vs. women) and cardiovascular fitness status (active vs. sedentary) on the cardiorespiratory indices [e.g., the myocardial volume oxygen (MvO2), forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC)] at pre- and post-exercise status in an air-polluted environment. Method: 120 participants (46 ± 5 years) were classified into experimental and control categories and two subgroups; including physical fitness status (active vs. sedentary) and sexes (men vs. women). The heart rate variability and cardiorespiratory indices were measured at different times of performing the exhaustive exercise. Results: At rest condition, higher MvO2 values were detected in the experimental groups in comparison to women in the control groups (p < 0.001). Performing the exhaustive exercise in the polluted ambient caused lower RMSSD and higher MvO2 indices in experimental groups (p < 0.001). Exposure to air pollution could negatively alter cardio-autonomic and respiratory systems among sedentary and active women (p < 0.001). Conclusion: In air-polluted ambient, the exhaustive exercise increases myocardial stress in both sexes, regardless of cardiovascular fitness status.