Q: I was wondering if you could tell me when I am suppose to inhale and when I am suppose to exhale when training?
A: It is pretty simple once you get the hang of it. Basically, there are two parts to an exercise: 1. The concentric and 2. The eccentric. Concentric is when the shortening of the muscle occurs and eccentric is when the lengthening occurs. For example during a dumbbell curl the concentric contraction is when you are curling up towards your chest and the eccentric is when you are lowering the dumbbell back down to the starting position.
When you are lifting weights you should be breathing out on the concentric movement when you are exerting, and breathing in on the eccentric portion.
DO NOT hold your breath because it is important that you supply your muscles with oxygen. If you hold your breath for too long you while exerting too much you could put yourself at risk for a hernia, and no one wants that. Also if you hold your breath for too long you could make yourself dizzy.