October 4, 2022

expert reaction to study looking at transgender women’s heart-lung capacity against cisgender peers after years of hormone therapy

A study published in British Journal of Sports Medicine looks at cardiopulmonary capacity and muscle strength in transgender women on long-term gender-affirming hormone therapy.

Dr Channa Jayasena, Clinical Senior Lecturer and Consultant in Reproductive Endocrinology and Andrology, Imperial College London, said:

“This small yet well-designed study compared lots of measurements linked to physical performance in transwomen, cis-gender women and cis-gender men. They found differences in muscle development, strength and oxygen usage between the transwomen and cis-gender women. This suggests that there are likely to be small differences in how the muscles work between trans- and cis-gender women. However, none of the participants were athletes. And, it is possible that there are similar differences in muscle function are found among cis-gender athletes.”

Prof Alun Williams, Professor of Sport and Exercise Genomics, Manchester Metropolitan University, said:

“Strong points of the study are the transwomen had received hormone treatment for several years, and the assessment of cardiovascular fitness (VO2peak), but weak aspects of the study are tests of muscle strength and body composition that could be done better, the cross-sectional study design, and (if trying to inform policy) studying non-athletes. Nevertheless, the pattern of results, i.e. transwomen performance generally between that of cisgender men and women, supports studies using shorter periods of hormone treatment – therefore, this new evidence doesn’t support the eligibility of transwomen for the female categories of most sports. Studies of well-trained athletes before and during their treatment, using tests that are more accurate and more relevant to competitive sport, are required to better inform sport eligibility policies.”

‘Cardiopulmonary capacity and muscle strength in transgender women on long-term gender-affirming hormone therapy: a cross-sectional study’ by Leonardo Azevedo Mobilia Alvares et al. was published in the British Journal of Sports Medicine at 23:30 hours UK Time Tuesday 4 October 2022.

DOI: 10.1136/bjsports-2021-105400

Declared interests

Dr Channa Jayasena: “No conflicts.”

Prof Alun Williams:

• Current research grant funding includes the International Olympic Committee (IOC) regarding the effects of lowering testosterone on physical performance in transwomen
• Fellow of the British Association of Sport and Exercise Sciences (BASES) and co-author of two BASES Expert Statements regarding female sport category eligibility of (1) transwomen and (2) athletes with differences in sex development (DSDs)
• Independent Expert Witness in the 2019 case at the Court of Arbitration for Sport (CAS) of Caster Semenya vs. IAAF (now World Athletics)
• Consulted in 2022 by World Triathlon, and the Welsh Rugby Union, regarding policies concerning transwomen eligibility for female competitive categories