The menopausal transition does not influence skeletal muscle capillary growth in response to cycle training in women
The influence of the menopausal transition, with a consequent loss of oestrogen, on capillary growth in response to exercise training remains unknown. In the present study, we evaluated the effect of a period of intense endurance training on skeletal muscle angiogenesis in late pre-menopausal and recently post-menopausal women with an age difference of <4 years. Skeletal muscle biopsies were obtained from the thigh muscle prior to and after 12 weeks of intense aerobic cycle training, and analyzed for capillarization, fiber type distribution and content of vascular endothelial growth factor (VEGF). At baseline, there was no difference in capillary per fiber ratio (C:F; 1.41 ± 0.22 vs 1.40 ± 0.30), capillary density (CD; 305±61 vs 336±52 mm2), muscle fiber area (MFA) or percentage distribution of muscle fiber type I (47.3±10.1 vs 49.3±15.1 %) and type II (52.7±10.1 vs 50.7±15.1%) between the pre- and post-menopausal women. The training period resulted in a similar increase in C:F in pre- and post-menopausal women (by 9.2 vs 12.1 %, respectively) and CD (by 6.9 vs 8.9 %, respectively), whereas MFA and fiber type distribution remained unaltered. Skeletal muscle VEGF protein content was similar between groups at baseline and increased to a similar extent with training (by 21.1 vs 27.2 %, respectively) in the pre- and post-menopausal women. In conclusion, the loss of oestrogen per se at menopause does not influence the capillary growth response to intense aerobic exercise training.