The menopause alters aerobic adaptations to high-intensity interval training

Abstract

Introduction: Post-menopausal women have lower resting cardiac function than pre- menopausal women, but whether the menopause influences maximal cardiac output and hence exercise capacity is unclear. It is possible that pre- and post-menopausal women ̇ achieve similar improvements in peak aerobic capacity (V O2peak) and cardiac output with exercise training via different regional left ventricular muscle function (“LV mechanics”), as suggested by in vitro and animal studies. The aim of this study was to investigate the effects of the menopause on LV mechanics and adaptations to exercise training. Methods: Twenty-five healthy untrained middle-aged women (age 45–58 years; 11 pre-menopausal, 14 post-menopausal) completed 12 weeks of exercise training. Before and after exercise ̇ assessed using echocardiography at rest and during two submaximal physiological tests — lower body negative pressure (LBNP) and supine cycling. Results: The increase ̇ training, (i) V O2peak and blood volume were determined, and (ii) LV mechanics were in relative V O2peak after exercise training was 9% smaller in post-menopausal than pre- menopausal women, concomitant with a smaller increase in blood volume (P < 0.05). However, cardiac output and LV volumes were not different between pre- and post- menopausal women (P > 0.05) despite altered regional LV muscle function, as indicated by higher basal mechanics in pre-menopausal women during the physiological tests after exercise training (P < 0.05). Conclusion: These findings are the first to confirm altered LV mechanics in post-menopausal women. In addition, the reduced aerobic adaptability to exercise training in post-menopausal women does not appear to be a central cardiac limitation, and may be due to altered blood volume distribution and lower peripheral adaptations.