Intermodal comparison of energy expenditure at exercise intensities corresponding to the perceptual preference range

Purpose: This study compared the rate of energy expenditure among six popul ar exercise machines at intensities corresponding to ratings of perceived e xertion (RPE) for fairly light (RPE-11), somewhat hard (RPE-13). and hard ( RPE-15) in 9 healthy men and 10 healthy women. Methods: A maximal exercise test on each exercise machine was used to anchor the Borg 15-point category scale. Subjects performed three submaximal exercise tests at selected RPEs on a treadmill. stair-stepper, cycle ergometer, rowing ergometer. cross-co untry ski simulator, and rider. The submaximal tests on each exercise devic e were performed in random order and were 6 min in duration with 15-min res t between trials. Oxygen uptake, heart rate, and blood lactate concentratio n were measured during the final 2 min of each exercise intensity. Results: Energy expenditure at each RPE was highest on the treadmill and ski simula tor in men, and on the treadmill, ski simulator, and rowing ergometer in wo men. Energy expenditure in men and women at all RPEs was lowest on the ride r and cycle ergometer. Energy expenditure at a given RPE was greater in men than women on all exercise machines, but men and women used a similar perc entage of their machine specific peak oxygen uptake at each RPE on all mach ines. Heart rate was generally similar among the machines and between both men and women at each RPE. Conclusions: Our results indicated that there ar e large differences in energy expenditure between exercise machines and bet ween men and women at intensities perceived to be fairly light, somewhat ha rd. and hard. Consequently, subjects can expend more calories at the same R PE during treadmill and ski simulator exercise. for example, than during ex ercise with other devices. This may have important implications for the hea lth benefits of different exercises and in promoting long term exercise adh erence.