Thanks for the replies. I understand how important cardio is for general overall health, but I am still unclear as to whether it impedes mass gain. For example say you have two people:
-Person A: does 20-30 min daily cardio at 70% max heart rate and expends approx 250 cals doing so. Eats 3250 calories/day.
-Person B: no cardio. Eats 3000 calories/day.
Will person B gain more mass/strength than person A?[/quote]
I think the only answer that’s definitely true is “it depends.” It depends on how much of a constellation of different hormones your endocrine system produces in response to the cardio, and on the sensitivity of your various tissues (muscle, fat) to those hormones. These factors are different for different people, and probably the best way to determine what works best for you is to experiment on yourself: If you’ve been doing cardio for a while, try dropping it for a month (or cutting it in half), while keeping your training & diet the same, and see how your lifts/LBM/body comp change.
For more information (but no definitive answers) read these: