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Cardio and Muscle Loss??


can someone please direct me to an explanation of the connection between cardio and muscle loss?

for example, at what intensity does muscle loss begin?


I'm no expert by any means, but there have been studies that show that high intensity cardio reduces muscle growth and may even break down muscle fibres to use as an energy source.

For fat loss try 40-60% of your heart rate [as is suggested on the treadmills at the gym :p] or if following a hardcore diet such as Velocity, walking with a weighted vest or sandbag in a backpack works well too. Can't beleive nobody has answered to this post yet. C'mon guys the newbies are the ripped guys of tomorrow :wink: Hope this helps anyhow - c.j

Edit: as i said, not an expert and that my version was simple, but thought it wierd that nobody had replied up until now :s listen to phill and mic as both are much more knoweledgable :stuck_out_tongue:


Well your Largest concerns are really diet and Amount more then Type to start.

If well fed and not running for HOURS then really you dont have To much to worry about. Now if you are doing endurance type stuff then sure the body just wont want to carry that extra muscle and will fight it. Ity doesnt feel its needed for the task you are asking it to do. It wants you lighter and muscle weighs a LOT if you are running for mile upon mile.

Then there are types of cardio that are more anabolic in nature like HIIT, sprinting etc. Look at the physique of a sprinter and look at that of a marathoin runner. Enough said

Now if on a restricted diet then its touchier. You are in a not well fed state low on fuel etc. You push that cardio up and out of the Low slow fat bruning zone 60% or so max (rough estimate) and start making that muscle tap ionto the limited glycogen (faster) fuel It burns those limitied resevrevs FAST and then has to create more, how by making it from protein, your not fed it uses that muscle, that muscle it Doesnt feel it needs to LIVE to RUN.

That is EXTREMELY simple/quick version. Do yourself a favor and read up more.

There is a recent article on cardio with many of the contribs and try these oldie but goodies for a great over view as well.

Cardio Roundatble I&II

Hope that helps,


I'm afraid it's not that simple. The following two articles should give you a good synopsis of the topic:

Cardio Roundtable 1 and 2:


Fasted Cardio Roundtable:


Edited: Phill was quicker. Anyway, read it!


Whats up? This is my first post here. Great site!

I've read articles that cardio promotes testosterone production and I've read articles explain the catabolic aspects of cardio. I was thinking about this question a while back. I looked at the Olypic Sprinters and NFL players and realized that sprinting was probably the best thing you can do to promote vascularity and shed unwanted body fat. You can tell the huge difference between them and Long distance runners.

I tried a routine that had incorporated sprinting and I got stronger, more ripped and it was less time consuming.

Good luck!