Harper: Absolutely. 95% of cisgender girls have testosterone below 2 nanomoles per liter. And in a recent study of almost 250 trans girls, 94% of them had testosterone beneath 2 nanomoles per liter.
It does not actually matter whether or not the restrict is 5 or 10 nanomoles per liter as a result of most trans girls are going to be below 2 anyway.
Hemoglobin ranges are larger in males, which permits extra oxygen to get into the muscle mass. Is the principle benefit of that higher endurance as a result of muscle mass do not fatigue as rapidly?
Harper: Yes, the one most necessary physiological issue for endurance athletes is hemoglobin. In sports activities it’s typically measured as hematocrit ranges. Hematocrit is the proportion of blood that is pink blood cells.
That’s the explanation that endurance athletes go to altitude to coach, or [those who cheat] use blood doping or EPO. There are a number of issues that go into making an endurance athlete, however the single most necessary issue can be hemoglobin levels.
Hemoglobin ranges additionally drop as testosterone ranges decline, proper?
Harper: Hemoglobin ranges observe the testosterone. Within weeks of beginning testosterone suppression, testosterone ranges can be inside feminine norms, but it surely takes a bit of longer for hemoglobin to get the female norms, in all probability within the 3- to 4-month vary. That’s roughly the life cycle of pink blood cells.
As trans girls substitute their pink blood cells, with their new decrease testosterone ranges, they are going to have fewer pink blood cells and decrease hemoglobin, but it surely does take 3 to 4 months.
What distances are we usually speaking about the place endurance is a bonus — is it an 800-meter observe occasion, or is it extra within the 1,500 meters and above vary?
Harper: The 800 meters is probably going extra pace than endurance. You’re in all probability speaking 1,500 meters and above, however that’s simply observe. There’s [also] distance swimming, distance biking, the triathlon. There are any variety of endurance kind sports activities.
How are different potential benefits comparable to lean physique mass and energy affected by medical transition?
Harper: Lean physique mass and energy are much less affected than hemoglobin, however we do not actually have research on trans athletes. Our review and another one checked out research on non-athletes. One of the necessary issues to notice is that even earlier than beginning hormone therapy, the trans girls in these research have been considerably much less robust than cis males. I put it colloquially that as a inhabitants group, trans girls would moderately starve themselves to appear to be fashions, than placed on muscle to be athletes.
