The influence of fitness and body weight on preferred exercise intensity

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.

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 (VO(2)), HR, percentage of maximal oxygen uptake (VO(2max)), percentage of HRmax (%HRmax), RPE for the overall body, TM belt speed, and total energy expenditure (EE).

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) VO(2max) (52.4 vs 39.56) than the higher-fitness subjects.

These findings suggest that fitness, and not body weight, influences preferred exercise intensity as measured by VO(2max) during TM walking in college-age women. The self-selected walking speed did not result in an intensity, as determined by VO(2max), that is consistent with the enhancement of cardiorespiratory fitness for higher-fitness women regardless of body weight.