After the 'hold' it is important to return to the original position slowly for the same reasons as already given. . The number of times given to repeat each exercise is only a recommendation and is really a minimum. Obviously, the more you do the better but do not try doing too much. You must not miss any of the exercises out. Try avoiding this and breath normally at all times.
Normal breathing means breathing at a rate dictated by the body.
If you are working hard during exercises you may begin to pant because your body is demanding more oxygen. Holding your breath while under 'strain' is not helping. . You are doing this because it's good for your body. You are doing this because it's good for your mind. You are doing this because you want to.