Differences between Males and Females in Determining Exercise Intensity.

Even though there are physiological differences between males and females, heart rate (HR), ratings of perceived exertion (RPE), power output (PO), oxygen consumption (VO), and blood lactate (BL) levels have been used as measures of exercise intensity independently of sex. The purpose of this study was to determine differences between sexes in different exercise intensity models. Thirty (15 females) young, healthy individuals were scheduled for two testing visits 48-72 hours apart. During the first testing visit, a graded exercise test (GXT), with BL obtained at the end of each exercise step, was administered on a stationary bicycle to determine peak PO and VOmax. BL during the GXT was used to determine three 5-min steady-state workloads (low: 0-2 mmol/L; moderate: 2-4 mmol/L; and high: >4 mmol/L) for the second test. HR, %HRmax, RPE, PO, %POmax, VO, %VOmax, and BL were obtained at the end of each steady-state workload. A two-way repeated measures ANOVA was performed to compare all exercise intensity variables obtained during the second test between males and females (α=0.05). Only RPE, %PO, and BL did not differ between sexes on all 3 exercise intensities. HR, %HR, and PO differ between sexes on at least 2 exercise intensities. Females have higher HR and %HR than males for similar %PO. VO and %VOmax differ between sexes on at least 1 exercise intensity. Based on the current results, traditional exercise intensity markers are different between males and females. BL and %PO appear to be markers that might be used independently of sex.