Cardio question

[oso0960]

I've been reading about HIIT vs steady state and am confused about how the body uses different sources for fuel. People say that 85% and up of max HR use mostly carbs as a fuel source and anything lower uses mostly fats. How do we know this?

Assuming it's true, why would the body use LBM for fuel instead of fatty tissue or fats if doing HIIT without carbs?

 

[timtim]

I've been reading about HIIT vs steady state and am confused about how the body uses different sources for fuel. People say that 85% and up of max HR use mostly carbs as a fuel source and anything lower uses mostly fats. How do we know this?

Assuming it's true, why would the body use LBM for fuel instead of fatty tissue or fats if doing HIIT without carbs?

look up adenosine triphosphate. the systems by which fuel is used in the body will be there. different mechanisms require different fuel.

 

[oso0960]

Hah I should've remembered that from biology class a couple years back. Thanks timtim.