Generalized obesity but not that characterized by raised waist-hip ratio is associated with increased perceived breathlessness during treadmill exercise testing

The management of obesity is linked to defining its impact on exercise. One impact of obesity in coronary disease care is in the quantification of exercise limitation by treadmill protocols. In this study, we considered the impact of obesity as definition by body mass index (BMI) or waist-hip ratio (WHR) on perceived exercise limiting symptoms, which are accepted and valuable targets for drug or lifestyle modification. We gathered morphometric data prospectively using bioimpedance (Bodystat® Quadscan 3000), BMI, and WHR in 228 unselected cardiac patients attending for diagnostic Bruce treadmill tests. The patients were categorized as obese (BMI >30 kg/m²), overweight (BMI 25.0-29.9 kg/m²), or normal weight (BMI <25 kg/m²). A quantitative visual analog scale (10 cm) of perceived breathlessness was defined by the subjects at the end of each stage along with standard exercise data. In total, 188 patients were included for the final analysis excluding 12 patients with severe LV dysfunction and 10 patients with severe inducible ischemia necessitating an early termination of the test. There was no difference by obesity indices in the distribution of reasons for stopping the test (elective arrhythmia, inducible ischemia, or intolerable functional symptoms). Perceived symptom score on the visual analog scale were persistently higher at the end of stages 1, 2, and 3 of the Bruce protocol in obese individuals as compared with overweight and normal weight subjects. (P = 0.034, 0.003, and 0.042, respectively). Perceived symptoms during exercise when assessed by WHR did not show any statistical difference in severity. Generalized obesity associated with a high BMI is associated with increased perceived breathlessness during standard exercise testing regardless of ischemia or known left ventricular systolic function. This clearly indicates that perceived breathlessness does not correlate with obesity as defined by WHR, which is known to be a more sensitive marker of coronary disease. Therapeutic interventions in obesity should take into account the frame of reference of definition of obesity.