Trans women on long-term hormone therapy might have similar oxygen levels and fitness as cis women, even after going through male puberty.

For transgender women on long-term hormone therapy, how well their bodies use oxygen during exercise is closely linked to their muscle mass relative to height — but this doesn’t seem to be the case for cisgender men or women.

When you account for muscle mass, trans women, cis women, and cis men have about the same heart and lung fitness level — even if their raw numbers look different.

Trans women who've been on hormone therapy for years can take in more oxygen during intense exercise than cis women, but less than cis men — putting their heart and lung fitness somewhere in the middle.

Even after years of hormone therapy, transgender women might still be able to do more push-ups than cisgender women on average, possibly because some strength differences stick around longer than expected.

When transgender women take estrogen for a few years, their weight tends to go up a little, but when transgender men take testosterone, their weight usually stays about the same.