I just wrote in a comment about this and decided I might as well make a post to see what people think.
I am transitioning, in short simple terms I was born neurologically a boy (gender) but my body including my internal organs and hormones (sex in other words) was female. So I'm taking testosterone gel and later having surgeries to make my sex match my gender.
My personal best peak flow before I started testosterone was 380. I started in November 2016, and was hospitalised with a life-threatening asthma attack in December 2016. When I got out my peak flow hovered at 310-330 for a month or so so I gave up tracking it.
Fast forward to the end of May, coming up to 7 months on testosterone, when I had an asthma review. I did spirometry tests and my PEFR came out as 435. I was like "no way, that must be the old scale", because I'd never blown even close to that before, and my lungs felt iffy anyway (cough, bit tight, stuffy in the mornings). So the nurse gave me an EU scale peak flow meter..and I got 435 again. Wow!
It's also July now, so I haven't been hospitalised in 6 whole months. Last in the past two years I was hospitalised: August 2015; December 2015; May-June 2016, and December 2016. So I was expecting to be in again a couple of months ago..and I'm still not in.
Coincidence? Or could the testosterone have helped my lungs in some way?