Abstract MP80: Increased Physical Fitness Is Associated With Greater Improvement In Cardiac Parasympathetic Function Among The Obese Than Overweight Or Normal Weight Individuals
Introduction: The impact of physical fitness on heart rate recovery (HRR), a marker of cardiac parasympathetic activity, has rarely been studied across weight categories. We examined the effect of physical fitness across different weight categories on HRR at 2 minutes after exercise stress test in an asymptomatic cohort.
Methods: This is a cross-sectional analysis of 525 Brazilian subjects, free of known cardiovascular disease that underwent exercise stress test. Metabolic equivalents at maximal exercise (METS) were calculated from the volume of oxygen consumed during maximal exercise (VO2max). HRR was defined as peak exercise HR minus HR after 2minutes rest. Weight was classified into obese (BMI ≥ 30), overweight (BMI 25 -29) and normal weight (BMI <25).
Results: The prevalence of overweight and obesity was 51% and 19% respectively. There was a positive significant correlation between METS and HRR (r= 0.34 p<0.001). The mean HRR was higher among the normal weight than the overweight or obese (92 vs. 89 vs.76 beats; p<0.001) while the average (mean) METS decreased across increasing weight categories (10.6 vs. 10.4 vs. 9.1 METS; p <0.001). In a fully adjusted linear regression model, for every unit increase in METS the HRR increased by 2.0 beats among the obese (p<0.005), 1.1 beats among the overweight (p<0.001) and 0.8 beats among the normal weight (p=0.143). These increases were significantly different among the 3 groups (p<0.001). Line fitted plots (figure below) showed that the increase in HRR associated with increasing METS was greater among the obese than the other weight groups and at high METS value (about 13 METS) the HRR are similar regardless of BMI.
Conclusion: Our findings suggest that increasing fitness increases HRR, with greater benefit in the obese than other weight groups. Physical fitness, not simply weight loss, should be advocated in the obese. More studies are required to fully understand the temporal relationship between BMI, physical fitness and HRR.
Author Disclosures: E. Aneni: None. E. Oni: None. L. Roberson: None. R. Meneghelo: None. M. Blaha: None. R. Blumenthal: None. J. Post: None. A.S. Agatston: None. T. Feldman: None. R.D. Conceiçao: None. J. Carvalho: None. R.D. Santos: None. K. Nasir: None.
- © 2014 by American Heart Association, Inc.