Sex differences in heart rate responses to sub-maximal exercise in young adults
There is paucity of scientific information on sex differences in heart rate (HR) responses during and after a sub-maximal exercise test in young adults. We assessed sex differences in normal HR responses during and after a sub-maximal-effort cycle ergometer exercise test in apparently healthy young adults. One hundred young adults (50 males and 50 females) participated in the study. Subjects performed a sub-maximal exercise at an intensity that produced 60–85% of a pre-determined age-predicted maximum HR. Measurements of subjects’ HR were done at rest, during exercise and post exercise recovery periods. The present data indicated that after adjusting for covariates, greater (P<0.05) HR responses (delta HR 2 min, delta HR 5 min, delta peak HR) were observed in men relative to women. Males also indicated significantly higher (P<0.05) %HRmax and %HRreserve compared to females. Variables of HR response during post-exercise recovery did not differ between males and females. HR responses during exercise were greater in young adult males compared to females while HR responses at post-exercise recovery were similar between the two groups. The present findings may be useful in interpreting more accurately the significance of HR responses during and after exercise in healthy young adults according to sex.