EFFECTS OF MODE OF EXERCISE AND GENDER ON OXYGEN CONSUMPTION, RATINGS OF PERCEIVED EXERTION, AND LACTATE AT EQUATED HEART RATE INTENSITIES1134

Abstract

Heart rate (HR) has long been used as a gross indicator of exercise intensity for both aerobic and circuit weight training exercise regimens. Previous research supports the differential responses of oxygen consumption(VO2), HR, ratings of perceived exertion (RPE), and lactate production(LA) due to these different modes of exercise. However, little research has been conducted on the responses of these parameters between the different modes at similar HRs. The purpose of this investigation was to determine differences between a low intensity cycle ergometry (CE) exercise and a modified circuit training leg press (LP) exercise at similar steady state (SS) HRs. Twelve subjects (6 men 24±5 yr, 73±11 kg, 180±3 cm; and 6 women 22±2 yr, 55± 6 kg, 161±8 cm) performed two preliminary tests on separate days to determine mode specific exercise intensities between 65-70% maximum HR for both exercises. The LP was performed on a Nautilus Duo-Leg Press and consisted of a bi-pedal, rhythmic cadence controlled by metronome. During the final exercise test VO2, RPE, and LA were collected. Venous blood samples were collected via syringe and stopcock method at rest, 2 min., SS, and 2 min. post and VO2 was determined for SS using Douglas Bags and Beckman Analyzers. RPE was recorded at one minute intervals during the test. HRs were determined with Polar HR Monitors. Results of ANOVA with repeated measures and statistical significance(p<.05) show that RPE differs for the modes at similar SS HRs (CE 10±3 and LP 14±2). VO2 was also significantly different(CE 20.62±7.39 ml/kg/min and LP 14.27±3.82). LAs were not significantly different between exercises. Gender effect at similar SS HRs showed no statistical differences between men and women for VO2, RPE, or LA. Circuit training and cycle exercise, when performed at similar HR intensities, do cause differential responses. HR is not a good predictor of circuit training intensity, especially when considering VO2 and perceptual stress.