Body composition and muscle performance during menopause and hormone replacement therapy.

Menopausal transition is characterized by ovarian failure and its consequent decrease in female sex steroid production. Earlier studies suggest that an increase and redistribution of body fat during menopause predispose women to cardiovascular disease and metabolic syndrome. In addition, peri- and post-menopausal women seem to have less lean body mass (LBM) compared with pre-menopausal women. Accordingly, a changing ovarian hormonal status may accelerate the loss of muscle mass and result in decreased muscle performance and functional capacity. Hormone replacement therapy (HRT) has been used to treat menopausal symptoms and as a primary prevention therapy in chronic conditions. Inconsistent findings have, however, been published on the effects of HRT on body composition in post-menopausal women. Some studies clearly suggest that HRT counteracts menopause-related changes in body composition whereas others fail to show any difference between post-menopausal HRT users and abstainers. Although cross-sectional studies show conflicting results concerning the association between HRT and muscle performance, experimental trials suggest that deterioration in muscle force during menopause can be prevented by HRT. In the future, longitudinal data need to be collected to confirm changes in body composition and muscle performance during menopausal transition irrespective of age. Although HRT seems to have beneficial effects on body composition and muscle performance in healthy post-menopausal women, there is considerable variation in the effects of HRT between different studies. The underlying mechanism of HRT action on muscle performance is still unclear.