Cardiac output differences in males and females during mild cycle ergometer exercise

Abstract

FREEDSON, PATTY, VICTOR L. KATCH, STANLEY SADY, and ARTHUR WELTMAN. Cardiac output differences in males and females during mild cycle ergometer exercise. Med. Sci. Sports. Vol. 11, No. 1, pp. 16-19, 1979. To study sex differences in cardiac output during submaximum exercise, eight male and eight female subjects were matched on max V̇o₂ (1 min^-1 and ml kg^-1min^-1). Each subject performed one, eight minute submaximum bicycle ergometer test at 35% of V̇o₂max (300 kpm min^-1). At a steady state mean V̇o₂ of 0.96 1 min^-1, cardiac output was determined. Significant differences between men and women were observed (p<.05) in cardiac output, stroke volume and (a-v) O₂ difference. The males had a lower cardiac output (1.75 1 min^-1) and stroke volume (17.2 ml beat^-1) and a higher (a-v) O₂ difference (2.01 vol %). When these variables were expressed independent of lean body weight the above differences were non-significant. It was suggested that cardiac output differences between the sexes during mild exercise are due, in part, to differences in lean body weight.

CARDIAC OUTPUT, (A-V) O₂ DIFFERENCES, STROKE VOLUME, SEX DIFFERENCES, EXERCISE, LEAN BODY MASS