VO2 AND RPE DURING TREADMILL AND STAIRSTEP EXERCISES AT A GIVEN HEART RATE

Abstract

421 Exercise is often prescribed based on % of heart rate reserve (%HRR), given that %HRR is directly related to %VO2max and rating of perceived exertion (RPE). Although these relationships may hold for treadmill exercise, they may not for other modes of exercise. The purpose of this study was to compare %VO2max and RPE between stairstep ergometer (SS) and treadmill (TM) steady state exercise performed at a similar heart rate (HR). Sixteen healthy men and women (age: 22.9 ± 0.8 yr; body mass: 72.5 ± 2.9 kg, mean ± SE) performed TM and SS maximal and submaximal tests on separate days. Submaximal intensity was set at 65% of HRR based on resting HR (68 ± 5 b·min−1) and from maximal HR determined during maximal TM. While maximum HR did not differ (197 ± 5 vs 200 ± 4 b·min−1) between SS and TM, VO2max for SS was 12% lower than TM (40.7 ± 3.6 vs 46.2 ± 2.0 ml·kg−1·min−1, p < 0.001). During the submaximal tests, %HRR and HR did not differ between SS and TM (66.9 ± 3.5 vs 66.2 ± 3.3% and 161 ± 3 vs 160 ± 3 b·min−1, respectively). Despite the similar HR during submaximal exercise, VO2 during SS was lower (28.7 ± 1.6 vs 31.2 ± 1.6 ml·kg−1·min−1, p < 0.001) and RPE was greater (12.6 ± 0.6 vs 10.9 ± 0.5, p < 0.01) than TM. During TM, %HRR did not differ from % TM VO2max (66.2 ± 3.3 vs 67.7 ± 2.4%). During SS, %HRR was greater than % TM VO2max (66.9 ± 3.5 vs 62.1 ± 2.4%, p < 0.01) but was similar to % SS VO2max (67.1 ± 3.2%). These data indicate that when %HRR is prescribed for stairstep exercise, the lower VO2 and higher RPE should be taken into account.