Purpose Versa Climber (VC) exercise has been compared to the treadmill and to leg ergometry for oxygen consumption at maximal exercise (VO2max), maximum heart rate (HR), and minute ventilation under maximal conditions VEmax, with conflicting results. Methods To clarify the physiological demands of VC exercise, 19 apparently healthy college students (12 men, 7 women) participated in submaximal and maximal exercise tests on the VC and treadmill. Results Initial treadmill VO2max tests revealed the subjects to be of average fitness for their respective age and gender (47.7 ± 4.3 for the men, for the women, 40.0 ± 2.3 mL/kg/min). Exercise tests were then performed randomly on both modes of exercise at intensities calculated to be 65% and then 80% of each subjects treadmill maximum HR. Finally, a maximal test was administered on the VC. The variables measured were HR, VO2, VE, systolic blood pressure, and perceived exertion (RPE). Rate-pressure product (RPP) was calculated for each submaximal intensity. The values attained for both maximum HR (189.1 ± 8.9 vs. 196.1 ± 7.9) and for VO2 at maximum HR (38.7 ± 6.2 vs. 44.9 ± 5.3) were significantly lower (P <0.01) on the VC. Submaximally, VO2 was significantly lower (P <0.01) on the VC at the 80% intensity (28.2 ± 5.6 vs. 31.5 ± 4.0) and RPP was significantly higher (P <0.01) on the VC at both the 65% (199.4 ± 30.8 vs. 176.8 ± 27.2) and 80% (265.5 ± 33.7 vs. 244.2 ± 24.9) of maximum HR intensities. Conclusions These results suggest that for HR based intensities, VC exercise may result in a lower energy expenditure than the treadmill, although there is a greater myocardial oxygen demand.