I have started running and noticed I am out of shape...what can I do to get into better shape as fast as possible? I am starting Army PT in late September and would not like to embarass myself. I am 6'4" @ 185 -- not fat, but would like to drop BF % but that will happen on it's own...not my main concern. Main concern is to work on breathing and not being out of breath as fast. My legs do not get tired from running really but I get out of breath fairly quickly. I wish to be able to run 2-3 miles without stopping at all and not be like completely dead afterwards. I have good running shoes and all and have started doing the stairs at the gym...it's like the endless stair case...I do it on a speed where I do ~100 flights in 20 minutes...this has made my legs stronger but I don't know if it helps much for respiratory conditions. I also do leg press, calf raises and squats. I also do eliptical and biking and obviously running every now and then when it's not too hot outside.