Abstract 11438: Clinical Determinants of Cardiorespiratory Fitness: The Cooper Center Longitudinal Study
Cardiorespiratory fitness (CRF) is widely accepted as an important reversible cardiovascular risk factor. In the current study, we studied the non-modifiable and modifiable determinants of cardiorespiratory fitness within a large healthy Caucasian population of men and women.
Methods: The current study includes 20,015 patients presenting to Cooper Clinic (Dallas, Texas) for a comprehensive medical examination between 2000-present. CRF was determined by maximum exercise testing. Physical activity index (PAI) was categorized into 5 categories: 0 = inactive; 1 = non-running activities; 2 = 0–10 miles/week running; 3 = 11–20 miles/week running; 4 = >20 miles/week running. Linear regression modeling was used to determine the most robust clinical factors associated with time achieved on treadmill.
Results: Age, sex, body mass index, and physical activity were the most important factors associated with fitness, explaining 56% percent of the variance of CRF (r2=0.56). The addition of all other factors combined (current smoking, systolic blood pressure, glucose, HDL and LDL cholesterol, health status) were associated with CRF (p<0.05) but additively only improve r2 by 2%. There was a significant interaction between BMI and physical activity on CRF, such that normal weight (BMI 20–24.9 kg/m2) individuals achieved higher fitness for a given level of physical activity compared to the obese (BMI ≥30 kg/m2) (figure). Percent (%) body fat, not lean body mass, was the key factor driving this interaction.
Conclusions: Body mass index and physical activity were the most important modifiable determinants of CRF. For a given level of physical activity, fitness achieved was greater among the normal weight compared to the obese. These data suggest normal weight individuals obtain the most cardiorespiratory fitness benefit from physical activity.
- © 2010 by American Heart Association, Inc.