Oxygen intake and cardiac output during maximal treadmill and bicycle exercise

Abstract

Oxygen intake and cardiac output were measured in 17 male students, aged 18–23 years, during maximal treadmill and bicycle ergometer exercise with stepwise incremental loading and constant loading. The average values of oxygen intake and cardiac output during treadmill exercise were higher than during bicycle ergometer exercise, either with incremental loading or constant loading. These differences were statistically significant (P < 0.001–0.01). No statistically significant differences are found in stroke volume, whereas significant differences were seen in maximum heart rate between all four different modes of exercise. Arteriovenous oxygen differences were higher during treadmill exercise than during bicycle ergometer exercise. It is suggested that lower maximum oxygen intake during bicycle ergometer exercise is related to the lower maximum cardiac output and lower arteriovenous oxygen differences as compared with treadmill exercise. maximum oxygen intake; maximum cardiac output; maximum heart rate; stroke volume during maximal exercise; arteriovenous oxygen difference during maximal exercise; comparison of treadmill and bicycle exercise