I’ve been thinking about this question again now that I’ve added cardio back into my week. Although I know HIIT is the coolest thing there ever was, I find it far too shocking to my system, so I just do old-school steady state cardio, twice a week, at high intensity for 60-70 minutes.
What I will do sometimes, if I have extra energy after 60 minutes, is switch to something like HIIT: 30 second all out effort followed by 30 second jog, and repeat for 5 minutes. This pretty much finishes me off completely.
People will say, “if you are doing 60+ minutes of high intensity cardio, you are burning muscle! Stop it!”
Am I? Because I am getting bigger despite adding my cardio back in. In fact, I was kind of stagnant until I added it.
Speaking totally unscientifically here, I think this idea is total bullshit. One explanation I’ve heard is that since muscle requires more calories to maintain, your body prefers to remove it first when under cardiovascular stress. Ehhh…?
Your body is bizarrely complex, and it does some weird stuff sometimes with regard to fat storage and cannibalizing muscle, but for the most part, it is a brilliantly assembled machine when it comes to being what it needs to be. If you are strength training 5 days a week, building muscle and getting stronger, while eating clean all the while, there is no logical reason your body would decide to break all of that down just because you decide to go for an hour run. Even if muscle does require more energy for maintenance, it is far more useful to you in the long run, and your body knows it.
What I think is going on is this:
You know those really fat guys who walk around the gym like bodybuilders? They can lift a ton, and they look huge and intimidating, but they have absolutely no definition whatsoever. Big, strong 20 inch arms that just look like tree trunks?
Ok, imagine that guy going home every night, measuring his arms, legs, chest, etc, and concluding his time in the gym is paying off. Then he adds cardio, and all that fat obscuring his muscle strips away. Now his 20″ arms are 16″ of cut muscle. Can you imagine this guy freaking out that he’s accidentally burned off all his muscle?
He hasn’t, of course, he just lost a crapload of fat.
That said, from what I’ve found, your body WILL consume muscle for protein when under starvation, or when under EXTREME, endurance cardio work. Like running a marathon. Other than that, you’re fine.
