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WHY Is Cardio Catabolic?


I see some suggestions about doing deadlifts, gpp, intervals etc, but really if he's looking for the endurance to run around for 1 hr straight with some sprints, his best bet is to run around for 1 + hr occasionally and some of the runs throw in some pick-ups to train for the ability to switch gears. If his goal were something along the lines of starting and stoping with breaks, i'd suggest the GPP, deads, etc.

Physiologically, there is a difference between doing 10 x 20 for squats with 10 sec rest and 1 hr out on the roads. The reason why the hour out on the roads can be catabolic, is, as many posters stated, adaptive for the body to run those distances for homeostasis. Also, the body switches type II fibers to type I, which would give a "catabolic" effect in the sense that you're losing these dense muscle fibers for the slow-twitch less dense muscle fibers. The type II fibers get exhausted and after this happens, you're only using type I, if your body does not have enough, it is very good, over a period of time, to switch the type II to type I.

Hopefully somebody got through that to understand what I was trying to say and comment on it. Just my observations from an endurance athlete aspect.


Isn't everything either catabolic or anabolic? Meaning things are either being broken down or they are being built.

I'm fairly new to this, but in that case, everything you do besides resting would be considered catabolic. Lifting weights is catabolic, running is catabolic, typing is catabolic, even eating is catabolic...but they yield anabolic results, later, when you're resting.


Yea, so more importantly, why do people look less favorably on the results that come from cardio?


Yes, but weight training has these same general hormonal effects. What's special about cardio? 2 things:

1) It preferrentialy causes the overall balance of fiber type expression to type I to shift toward type I and away from II.

2) If it is loaded it causes repeated eccentric induced microtrauma expecially around the tendons.

Its all relative. If you walk at 3 miles per hour up a 12% grade for 10 minutes 3 times a week, you may actually build some ham and calf muscle, and it can serve a a restorative workout by promoting blood flow. Walking uphill is great for lower back restoration.


"They're not trying to say that cardio is catabolic necessarily but that putting your body in a negative nitrogen balance is. the addition of long bouts of cardio will put your body in a negative nitrogen balance faster than weight training alone. i believe that as long as your nutrition is sound around these cardio sessions "



Lots of the studies done on the catabolic effects of Aerobic exercises are done with people who do stuff like long distance running and other endurance events. Many of these people eat high carb diets with low fat and protein with loads of defficiencies. Not to say all do, just most.