Too much cardio

[fitwes16]

Everyone always says do about 20 minutes of cardio to burn fat without burning muscle. If you go over that does it completely stop burning fat and go to muscle or only a little muscle? I need to burn more fat while keeping my muscle intact. I also do HIIT training. What should i do?

 

[junkfoodbad]

where did you hear this info? i dont think there is any certain time where all of a sudden it starts burning muscle for energy. It's just easier for the body to breakdown fat and use it for energy than muscle. So fat is always broken down first.

 

[stroutman81]

Junkfood is right, there is no hard evidence of doing too much cardio leading to "muscle fuel." What you heard is based on the fact that for individuals who have a hard time gaining muscle, doing to much cardio car inhibit their ability to gain muscle even more so. Some lunatics actually tell ectomorphs, individuals who are thin and have a hard time gaining muscle, to drop cardio all together. I call them lunatics b/c what good is your "muscular" body if your heart is out of condition?

If you have a hard time gaining muscle, I would focus on short bouts of cardio just as you are. 15-20 minute sessions 2-3 time per week using HIIT. Doing more won't necessarily lead to your fuel coming from muscle, but it can lead to overtraining. For the ectomorph, rest is the number one variable!