Exercise cardiac function in endurance-trained males versus females

Objective: To examine and compare the exercise cardiac function of enduranc e-trained (ET) women and men. Participants: Six ET women aged 20 to 29 years (mean VO(2)max = 64 ml . kg( -1) . min(-1)) and 9 ET men aged 20 to 29 years (mean VO(2)max = 69 ml . kg (-1) min(-1)) were included in the study. Main Outcome Measures: Cardiac output (Q), stroke volume (SV), diastolic fi lling rate (DFR), and left ventricular ejection rate (LVER) were compared a t rest and during exercise at heart rates (HRs) of 110, 130, 150, 170 bpm, and max. Resting blood volume (BV) and hemoglobin concentration ([Hb]) were also compared. Results: Compared to women, men had a higher BV and [Hb]. At HRmax, men had a higher Q (31.0 +/- 0.6 versus 24.1 +/- 0.9 1 . min(-1)), SV, DFR, and LV ER than women. When expressed relative to body mass (kg), there were no gen der differences in SVmax, and women had a significantly higher a-v DO(2)max (similar to 19%) than men. The SV of the men and women did not plateau at a submaximal level but continued to increase progressively to HRmax. During maximal exercise, the DFR was significantly faster than the LVER in the me n and the women. Conclusions: When ET men and women are matched for body mass, the gender di fference in SVmax is reduced so that it is no longer statistically signific ant. However, there are still significant gender differences in Q, DFR, LVE R, BV, and [Hb] that contribute to a higher VO(2)max (ml . kg(-1) . min(-1) ) in ET men compared to women. To augment SVmax, women and men rely to a gr eater extent on diastolic filling than on left ventricular emptying.