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20 Jan 2003

Too much cardio breaks down your muscle
Hi Fitness Doc

I have been told by many trainers and fitness fanatics that excessive cardio does more harm than good as it starts to break down muscle after a point.

The consensus has been that you should never do more than 45min of cardio a day, any more cardio after those 45min starts to have a negative effect and starts to break down muscle.

If this is true, please explain how this occurs.


Answer 315 views

01 Jan 0001

Hi Mel

This is not true. Under certain circumstances, there are chances of muscle breakdown, eg. under eating - therefore body uses muscles as protein (energy) source, or if you aren't properly trained and suddenly train excessively.

Furthermore, some degree of muscle break down occurs with excessive downhill running - but the instances are very specific as you can see, so don't think it all just happens after 45 mins of cardio. However, I still recommend a gradual build-up of exercise and not doing too much too soon.

Good luck!

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