This work sought to determine the fi tness responses and energy expenditure (EE) following once-weekly hill climbing for 16 weeks on diff erent slopes. A cohort of 98 healthy, sedentary subjects (49 female, 49 male) completed the program at their preferred climbing pace. Body composition, resting metabolic rate (RMR) and VO 2 max were measured. EE was measured on 4 slopes (11.6 °, 19.9 °, 14.9 °, and 28.6 °) at the subjects’ preferred speed. In males, weight, body mass index, fat mass signifi cantly decreased (P < 0.05), and RMR showed an increasing trend, but the difference was not signifi cant (P = 0.051). In females, the muscle mass increased signifi cantly, and fat ( %) and fat mass signifi cantly decreased (P < 0.05). Absolute and relative of VO 2 max, ventilation (VE) improved signifi cantly in both sexes (P < 0.01). Energy expenditure was similar on diff erent slopes, but shows gender-specifi c values of approximately 50.4 and 33.6 kJ/min for males and females, respectively. The regression equation of EE (kJ/min) = [1.724 × (female = 1, and male = 2) + ( − 0.072 × age) + 0.106 × weight + 0.024 × HR + 0.136 × slope + 1.487 × velocity] × 4.2. In conclusion, hill climbing at a subjects’ preferred velocity is a vigorous-intensity physical activity for energy cost and, performed once weekly, enhances cardiorespiratory fi tness and reduces fat mass, therefore making it a viable exercise for most people.