Are you holding your breath unconsciously?
It is a big issue when strength training, so much that it can actually prevent you from performing at your best. Although in big lifts (e.g. squats or deadlifts with a heavy weight) a controlled exhaling is suggested, for repeated reps, you need to really breathe quite a bit, otherwise the increased blood pressure will leave you powerless for the remaining sets. Many times I had to wait too long between the sets because of my blood pressure skyrocketing for exhaling too slowly. Now I have learned to do it better, I hold my breath just about enough to get me lifting the weight, and then exhale pretty quickly, and my blood pressure does not increase as much.
``Don't break the chain." -Jerry Seinfeld
``Moments of silence are part of the music." -Anonymous
| Body Fat %: 20.0