The influence of fitness and body weight on preferred exercise intensity

Abstract

Purpose: The purpose of this investigation was to determine the individual and combined effects of aerobic fitness and body weight on physiological responses, perceived exertion, and speed variables during self-selected steady-state treadmill (TM) walking in 60 healthy college-age women. Methods: The women were placed into one of four categories based on body mass index (BMI) and fitness level, assessed by a graded TM test. Subjects walked continuously on a TM at a self-selected pace for 15 min at a 2.5% grade. The dependent variables were oxygen uptake (V̇O2), HR, percentage of maximal oxygen uptake (%V̇O2max), percentage of HRmax (%HRmax), RPE for the overall body, TM belt speed, and total energy expenditure (EE). Results: There were no significant interactions or body weight main effects for any of the dependent variables. However, lower-fitness subjects walked at a TM speed that resulted in a higher (P < 0.0005) %V̇O2max (52.4 vs 39.56) than the higher-fitness subjects. Conclusion: These findings suggest that fitness, and not body weight, influences preferred exercise intensity as measured by %V̇O2max during TM walking in college-age women. The self-selected walking speed did not result in an intensity, as determined by %V̇O2max, that is consistent with the enhancement of cardiorespiratory fitness for higher-fitness women regardless of body weight. Copyright © 2006 by the American College of Sports Medicine.