ASSOCIATION BETWEEN HEART RATE VARIABILITY AND PHYSICAL ACTIVITY IN YOUNG MALE ADULTS

Recent studies have claimed a positive effect of physical activity on heart rate variability (HRV). Lower HRV is an indicator of autonomic dysfunction and is associated with sedentary lifestyle and cardiovascular diseases (CVD). Due to increased incidence of young adults having at least one CVD risk factor, this study aimed to determine the association between heart rate variability and physical activity in young male adults. This cross-sectional study was conducted in 31 apparently healthy university students (age: 21.2 ± 1.8 years; BMI: 20.3 ± 3.2 kg/m²). Physical activity was determined using International Physical Activity (IPAQ-short). HRV indices were measured while performing supine-to-standing manoeuvre and assessed using time and frequency domains. Standard deviation of successive differences between adjacent NN intervals (SDNN), which reflects the overall variability, was significantly higher in physically-active subjects (135.7 ± 48.4 ms) compared to the less active (99.4 ± 30.4 ms) (p=0.03). High-frequency (HF) power, a marker of vagal modulation, showed a greater trend in the physically-active (1290.7 ± 1335.4 ms) compared to the less active (728.3 ± 423.0 ms), however this was non-significant. Other HRV indices i.e low-frequency (LF) power and LF/HF ratio were not statistically different between both groups. No significant correlations were observed between HRV indices and time spent in physical activity. In conclusion, the physically-active individuals showed greater overall heart rate variability compared to the less active in response to orthostatic stress. Further studies with larger sample size and objective measurements of physical activity are warranted to elucidate the influence of physical activity on heart rate variability in young adults.