My husband, who used to be a body builder on a level of just doing it because he liked it, works out with me. He has always been good at reading his own body's reactions to different techniques and supplements. Anyway, he has always used the practice of performing his reps at very slow speeds with form as perfect as he could make it. He was never a social gym rat. He didn't yak and visit between sets. He always got very good results and built a lot of actual, useful, real world strength as well as a very nice, balanced physique.
All of this to establish his credibility. Along with much of the advice from published experts, he was careful to inhale on the lift and exhale on the negative end of each rep. Naturally, he has encouraged/instructed me to breathe the same way. However, he performed the lift with a slightly faster, but still deliberate rate and resisted gravity on the way 'down' ala isometrics. In contrast, I have been using the Slow Burn technique by Fred Hahn, which calls for very slow movement on both the lift and the release movements. I simply can't breathe in slowly enough to limit my inhaling to the lift. I find I must breathe both in and out, in a slow, deliberate way, matching it to the speed of my lift and also on the negative, or 'down' motion. It's supposed to take about thirty seconds to lift the weight and the same amount going down. Should I be able to inhale for thirty seconds? It would seem to me that if I am doing the same exertion to lift as to release, it wouldn't matter which motion gets the inhale and which gets the exhale.