Quote Originally Posted by Benq123 View Post
Definitely. Sprinting will make you more out of breath probably due to the muscles in lower body being bigger than upper. But boxing will still raise your HR alot and make you sweat so a good form of HIIT
The legs pull alot of oxygen from the blood. I remember when I was getting into dead lifting....in the beginning I would almost pass out at the top of a lift because I wasn't used to using my legs in that fashion. Same thing here. You gotta build it up, slowly.