The Menopause Alters Aerobic Adaptations to High-Intensity Interval Training

Abstract

Introduction: Post-menopausal women have lower resting cardiac function than premenopausal 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 O 2peak ) 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 training, (i)V O 2peak and blood volume were determined, and (ii) LV mechanics were assessed using echocardiography at rest and during two submaximal physiological tests -lower body negative pressure (LBNP) and supine cycling. Results: The increase in relativeV O 2peak after exercise training was 9% smaller in post-menopausal than premenopausal women, concomitant with a smaller increase in blood volume (P < 0.05).However, cardiac output and LV volumes were not different between pre-and postmenopausal 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.1 removed: Twenty-five healthy untrained 2 removed: completed

Echocardiographic Assessment of Myocardial Deformation during Exercise

“…The importance of regional LV deformation, at the LV apex, was again highlighted. Several other studies have revealed similar patterns of LV twist during exercise in pre-and postmenopausal women, in athletes and of humans ascending to high altitude [58][59][60][61][62]. Consequently, it is now generally accepted that an increase in LV twist with exercise up to moderate intensities can be expected as a normal response (Figure 3).…”

“…In this regard, Burns et al showed that aging seems to be associated with a reduced LV twist reserve during exercise in a population of 60-year old individuals [66]. Similarly, "female aging", as represented by the menopause, seems to impact the myocardial response to exercise, which may be further altered by exercise training [58]. One of the more surprising observations has been that of Cooke et al who proposed that endurance trained athletes with enlarged "athlete's heart" and a greater stroke volume had a similar systolic LV function, including LV twist, during submaximal exercise compared to untrained humans with smaller stroke volume [67].…”

A Contemporary Review of the Effects of Exercise Training on Cardiac Structure and Function and Cardiovascular Risk Profile: Insights From Imaging

“…A recent meta-analysis of 26 studies (n = 468 healthy individuals) found similar LV hypertrophy adaptations to endurance training among men and women, but that LV end-diastolic, end-systolic and stroke volumes increased more in men (31). In addition, women appear to experience greater improvements in arteriovenous oxygen difference with endurance training compared to men (32)(33)(34). The sex differences literature on exercise training responses is primarily limited to healthy adults, as the studies of patients with heart failure have been predominantly performed in men (35).…”

“…In younger, premenopausal women, the adaptations to endurance training are more likely related to peripheral determinants as opposed to LV adaptations, as seen in men ( 27 , 36 , 40 , 41 ). Older, post-menopausal women experience similar peripheral adaptations to endurance training but appear to have a smaller increase in peak VO2 and blood volume compared to premenopausal women ( 32 ). Spina et al demonstrated that among older (60–70 years) women, 9–12 months of endurance training increased peak VO 2 and arteriovenous oxygen difference, but LV end-diastolic and stroke volumes did not change ( 40 ).…”

“…Spina et al demonstrated that among older (60–70 years) women, 9–12 months of endurance training increased peak VO 2 and arteriovenous oxygen difference, but LV end-diastolic and stroke volumes did not change ( 40 ). Nio et al compared training responses to 12 weeks of endurance training among pre- vs. post-menopausal women and found that post-menopausal women experienced a smaller increase in peak VO 2 and blood volume, but no differences in cardiac output, heart rate, or LV volumes compared to premenopausal women ( 32 ).…”