Obesity Modifies the Effect of Fitness on Heart Rate Indices during Exercise Stress Testing in Asymptomatic Individuals

Abstract

Objective: To assess the impact of aerobic fitness on exercise heart rate (HR) indices in an asymptomatic cohort across different body mass index (BMI) categories. Methods: We performed a cross-sectional analysis of 506 working-class Brazilian subjects, free of known clinical cardiovascular disease (e.g. ischemic heart disease and stroke) who underwent an exercise stress test. Results: There was a significant trend towards decreased HR at peak exercise, HR recovery and chronotropic index (CI) measures as BMI increased, but resting HR increased significantly across BMI categories. In multivariate analysis, the change in CI per unit change in metabolic equivalents of task was greater among the obese subjects than the normal-weight (2.7 vs. -0.07; p interaction = 0.029) and overweight (2.7 vs. 0.7; p interaction = 0.044) subjects. A similar pattern was seen with peak HR and HR recovery, although the formal tests of interaction did not achieve statistical significance. Conclusion: Our findings strongly suggest that fitness is associated with a favorable HR profile and is modified by BMI. Intervention programs should place emphasis on fitness and not only on weight loss.

Relationship between adiposity and heart rate recovery following an exercise stress test in obese older women

“…In this study, after adjusting for covariates using hierarchical multiple regression percentage body fat, MET, and age were negative determinants of 1-minute HRR. The results are in line with three previous studies 10,13 , that a higher percentage body fat and age were associated with an impaired HRR. Moreover, a higher maximal MET level was associated with a better HRR following 1-minute post treadmill exercise testing.…”

“…In obese subjects, this impairment is reflected by reduced parasympathetic nervous system function and/or sympathetic nervous system overactivity 9 . Furthermore, a study in obese subjects with low levels of physical fitness revealed an impaired chronotropic index and HRR during and after exercise stress testing 10 . Several studies have shown that parameters of obesity negatively affect HRR following exercise [11][12][13] .…”

The effect of clinically elevated body mass index on physiological stress during manual lifting activities

“…Notably, the obese subjects had a 20% higher HR than the other two BMI groups. Previous studies reported that obese people have an elevated resting HR [43][44][45][46], which puts them at increased risk for cardiometabolic problems [47][48][49]. Cardiorespiratory fitness, which is more common among people of lower BMI, has been associated with a decrease in resting heart rate [50,51].…”