Hi! I am a 20 year old college student and I have always been weak (in that I always get tired easily, I did not play sports in school but whenever we had PE or something similar I would get tired easily and feel faintish sometimes!) . So I want to get healthy and increase my stamina. The things is, I'm skinny, so I need some advice and exercise tips on how I can increase my stamina and get toned WITHOUT losing weight? I'm really thin but I do want to be more active and have more strength.