Bill King said:Think of how much you walk during the entire day, is 20 mins really going to change much at all? NOPE
YES...20 min of sustained walking at a brisk pace each day can significantly increase your cardiovascular fitness...of course this is opposed to no exercise at all. Just because you are bulking does not mean you should neglect the rest of your health and fitness. Get out there and walk for 20-30min 3-4 times a week. You'll be better off for it in the long run.
JoBu