The impact of physical activity levels and cardiorespiratory fitness on heart rate variability in overweight and obese college students: a cross-sectional study.

High-intensity physical activity independently predicted both log(SDNN) and log(RMSSD) in overweight and obese college students.

• High-intensity PA predicted log(SDNN) with b = 0.40, 95% CI [0.12–0.67], P = 0.005
• High-intensity PA predicted log(RMSSD) with b = 0.48, 95% CI [0.13–0.83], P = 0.007
• Multiple linear regression models were used to identify these independent predictors of HRV
• Sample consisted of 184 overweight or obese college students in a cross-sectional design

Medium-intensity physical activity showed a significant independent effect on log(SDNN) but not on log(RMSSD).

• Medium-intensity PA predicted log(SDNN) with b = 0.22, 95% CI [0.04–0.39], P = 0.014
• Medium-intensity PA did not show a significant effect on log(RMSSD)
• PA intensity groups were categorized using the International Physical Activity Questionnaire-Short Form (IPAQ-SF) into low, medium, and high groups

Female participants exhibited higher parasympathetic HRV indices and lower sympathovagal balance compared with male participants.

• Females showed higher log(HFn) compared with males: b = 0.25, 95% CI [0.11–0.39], P < 0.001
• Females showed lower log(LF/HF) compared with males: b = -0.39, 95% CI [-0.62 to -0.17], P < 0.001
• These findings suggest sex-specific HRV patterns in overweight and obese college students

VO2max was not significantly associated with most HRV indices, remaining significant only for log(SDNN).

• VO2max predicted log(SDNN) with b = 0.46, 95% CI [0.02–0.90], P = 0.042
• VO2max was not significantly associated with log(RMSSD), log(HFn), or log(LF/HF)
• CRF was estimated from maximal oxygen uptake (VO2max) derived from a cycle ergometer test
• The association between PA and autonomic regulation appeared stronger than that between VO2max and HRV

Body composition was assessed alongside physical activity and cardiorespiratory fitness in a sample of overweight and obese college students.

• A total of 184 overweight or obese college students were enrolled in this cross-sectional study
• Body fat percentage and muscle mass were assessed using bioelectrical impedance analysis
• Resting HRV indices were obtained under standardized conditions
• Differences in body composition, CRF, and HRV were analyzed across PA intensity groups