oxidative energy pathway.....??

[bvonrod]

I was wondering if anyone had a concise way of explaining why cardio exercise mobilizes our stored fat to be used as energy? I've been told it takes 20 mins. for the fat to be broken down and passed into the bloodstream, is this accurate?

Secondly, it's well known that too much cardio can rob you of muscle mass. Again, can someone explain what happens to make this occur? Thanks all!

 

[Ironslave]

That isn't true that it takes 20 mins of cardio for fat to get in the blood stream. In the post absorptive (non fed) state, fat is the preferred substrate for energy. Gradually with exercise duration, you do begin to burn a higher percentage of calories from fat, however.

Sure, too much cardio can break down muscle. But it's not really that easy to do, if your diet is fine, and you're still training hard/heavy, and you're not doing boat loads of cardio (ie, hours a day), it shouldn't be very noticeable.

Check out this thread: if you have any specific questions (this is pretty open ended), don't be afraid to ask.

Introduction to exercise metabolism​

 

[bvonrod]

Wow, I'm hesitant to say that the thread made it crystal clear but it's rattling around in my head at the moment. I'm a newbie to this stuff. I guess what I was asking is from what I've learned the 3 energy systems are ATP-CP, Glycolysis and oxidative. Anaerobic exercise draws on the first two but as training duration increases and the intensity level decreases, the shift towards aerobic (fat for energy?) happens. If this is indeed true, WHAT is it about cardio that it has the tendency to prefer fat for energy? Or does this ONLY happen when glycogen stores are depleted? I was looking for a way to explain it in laymen terms possibly. Thanks.

 

[Achilles]

Great thread here guys. Really likes this kind of info

 

[67StingRay]

Bumping this old post.

 

[KaiGold]

Old one from 2009.