Impact of Sex on Cardiac Functional Adaptation to Different Modes of Exercise Training: A Randomized Cross-Over Study.

Purpose: We hypothesized that male and female volunteers would exhibit distinct changes in cardiac morphology, systolic, and diastolic function following endurance (END) and resistance (RES) training.

Methods: Thirty-eight females and 26 males participated in a randomized cross-over design trial in which all participants completed 12-weeks END and RES, separated by a 12-week washout. Echocardiograms assessed morphology (left ventricular mass, LVM), systolic function (ejection fraction, EF, and global longitudinal strain, GLS), diastolic function (mitral valve velocities, E, A; tissue Doppler velocities, e', a'), and left atrial volume.

Results: Males responded to RES by increasing LVM (Δ 9.1 ± 14.3 g, P = 0.005), while E/e' increased (Δ 0.74 ± 1.08, P = 0.004, indicating a decline in diastolic function). There were no significant changes in females following RES. In response to END, LVM increased in both males (Δ 8.8 ± 15.7 g, P = 0.008) and females (Δ 6.5 ± 12.5 g, P = 0.004), with no difference in E/e' (Δ -0.29 ± 0.90) in males but a significant difference in females (Δ -0.39 ± 1.06, P = 0.012, indicating an improvement in diastolic function). Systolic function was not impacted significantly by END or RES in either sex.

Conclusions: Our data suggests that females were less responsive to RES training than males, that RES increased LVM and caused a decline in diastolic function (i.e. an increase in E/e') in males, whereas END improved E/e' (i.e. decreased) in females. These data suggest that sex differences exist in cardiac structural and functional adaptations to different forms of exercise training.