Obesity and parasympathetic reactivation of the heart following exercise testing in young male adults: a pilot study

BACKGROUND: In elderly people, obesity may induce changes in the autonomic nervous system via alteration of the balance between the sympathetic and parasympathetic nervous systems. Little is known about obesity and parasympathetic reactivation following exercise testing, particularly in young people in Saudi Arabia, and its relationship with body composition parameters. OBJECTIVES: Compare parasympathetic reactivation using heart rate recovery (HRR) following the exercise test between young obese and nonobese people and explore the association between body composition parameters with HRR. DESIGNS: Cross-sectional study. SETTING: University research lab. PATIENTS AND METHODS: Twenty-seven young male college students underwent anthropometric measurements and treadmill exercise testing, during which the heart rate was monitored via 12-lead electro-cardiography. Participants were divided into a group (n=15) with high body fat percentage (>30%), and a group (n=12) with a normal body fat percentage (<30%) to compare multiple parameters including HRR, which was defined as the absolute change from heart rate (HR) peak during exercise to 1-minute post-HR peak. MAIN OUTCOME MEASURES: HRR, body mass index, waist-to-hip ratio, fat percentage, and trunk fat. SAMPLE SIZE AND CHARACTERISTICS: n=27, mean (SD) age=22.4 (0.98) years, range 21–25 years. RESULTS: There was no significant difference in HRR between the groups (32.20 [13.42] bpm for high body fat percentage vs 35.42 [13.35] bpm for normal body fat percentage) (P=.54). We found a non-significant inverse correlations of HRR with BMI (r=-0.18, P=.37), WHR (r=-0.04, P=.86), fat percentage (r=-0.18, P=.38) and trunk fat (r=-0.23, P=.25). CONCLUSION: HRR was preserved in our young obese people and was not different from nonobese people. Furthermore, it seems that obese people with higher body composition parameters may have slower HRR, or slower recovery indicating poorer parasympathetic reactivation. LIMITATIONS: Need a larger sample to confirm the findings of this pilot study. CONFLICT OF INTEREST: None.