The Impact of Gender Affirming Hormone Therapy on Physical Performance.

Abstract

The inclusion of transgender people in elite sport has been a topic of debate. This narrative review examines the impact of gender affirming hormone therapy (GAHT) on physical performance, muscle strength and markers of endurance. MEDLINE and Embase were searched using terms to define the population (transgender), intervention (GAHT) and physical performance outcomes. Existing literature is comprised of cross-sectional or small uncontrolled longitudinal studies of short duration. In non-athletic trans men starting testosterone therapy, within 1 year, muscle mass and strength increased, and by 3 years, physical performance (push-ups, sit-ups, run time) improved to the level of cisgender men.In non-athletic trans women, feminising hormone therapy increased fat mass by approximately 30% and decreased muscle mass by approximately 5% after 12 months and steadily declined beyond 3 years. Whilst absolute lean mass remains higher in trans women, relative percentage lean mass and fat mass (and muscle strength corrected for lean mass), hemoglobin and VO2 peak corrected for weight was no different to cisgender women. After 2 years of GAHT, no advantage was observed for physical performance measured by running time or in trans women. By 4 years, there was no advantage in sit-ups. Whilst push-ups performance declined in trans women, a statistical advantage remained relative to cisgender women. Limited evidence suggests that physical performance of non-athletic trans people who have undergone GAHT for at least 2 years approaches that of cisgender controls. Further controlled longitudinal research is needed in trans athletes and non-athletes.