HRT Improves Muscle Function in Postmenopausal Women

Hormone replacement therapy (HRT) has been found to improve muscle function at the cellular level. Dr Lars Larsson, from Uppsala University Hospital Sweden, and colleagues studied 6 postmenopausal monozygous female twin pairs (55–59 years old) in order to investigate the effects of HRT on muscle fibers and function. Only one of each twin pair was using HRT. Results showed that even though individual muscle fibers did not change in size, the muscles of HRT users showed greater strength by generating a higher maximum force compared to non-HRT users. HRT was also associated with a more efficient organization of myonuclei and improved muscle function. The results suggest that using HRT may, at least in part, reduce age-related modifications of muscle contractile proteins. The authors concluded that their findings “open a venue for future pharmacological interventions aiming at enhancing muscle mass and function in old age.”