Ok i heard if you get your heart rate going really high, it burns both fat and muscle. Is this true? I heard it usually only happens on the treadmill, but can it actully happen in weight training? It pisses me off if you get your heart rate going 80% it burns muscle, lol i like running fast and it bumps up there kind of fast.

that's bull****.

no its not, my personal fitness instructor yelled at me haha because my heart rate was 88%. He said im going to loose muscle too, and thats what I am trying to build.

first you ask if it's a myth or not, then when I say it is, you say no? Why ask if you have already made up your mind? what do you think your heartrate would be after 20 rep squats? (done with your 10 rm, the last 10 reps consists more or less of singles) now ask your trainer if the 20 rep squat program builds or burns muscle.

Well sorry for saying you are wronge, but this guy is a qualified trainer. I think he knows what he is talking about :S...i think

Not true.

Not true.

It's very unlikely you would burn much - if any - muscle as fuel during weight training

Weight training is primarily an anaerobic exercise and as such, it uses mostly sugars - and to a lessor extent - fat as the primary fuels for training.

Not true - it doesn't.

then why question him in the first place? You seem to believe anything anyone who's a qualified trainer says.. do you know what it takes to become a qualified trainer? Not a lot.

When your told that its a myth, you tell us we are wrong because your personal trainer is "certified". Most personal trainers are idiots and don't know **** about fitness. If you have already made up your mind, why are you posting in the first place?

I am with Wrangll and Karky on this one.

A high heart rate does not burn muscle. Look at most athletics, football, track and field. During training and competition the heart rate gets very high. Yet these athletes are still able to build muscle.

Weight training can increase the heart rate very high as well.

There is nothing, no research, no anything, that correlates a high heart rate with muscle loss.

Below are listed the only things (aside from disease, illness, or anything along those lines) that can lead to a decrease in muscle.

1. Not eating enough.
2. Long distance cardiovascular activity, done over a long period of time. (months, years) and generally, even then, only in people who have done weight training to increase muscular size first.
3. Not weight training, since muscle mass decreases as we age.

That's pretty much it.

I don't understand why you're asking. Either you are confident in his knowledge or you aren't. As you've made clear, you are so why ask? Nevertheless it's a crazy generalization and broad assumption. Nothing is that simple.

...and why would it only happen on the treadmill...?

I am also a "qualified trainer" and this is bull. It will burn muscle if you're completely out of glycogen, but you probably need a new trainer.

That is absurd.

Certified for what? how to lift a weight or turn on a treadmill..

the lower it bumps per minute, the better!

the lower it bumps per minute at rest, the better (unless it's abnormally low, offcource). Not necessarily during exercise..

It's not a myth. Once you breach around 80-85% of your heart rate max, your body becomes unable to generate enough energy through fat metabolism. It then has to rely more heavily on the already occurring carbohydrate metabolism to supplement its energy deficit. The key here is that with prolonged exercise your body is not able to supplement its energy requirements with carbohydrate metabolism alone because 1) it doesn't produce a whole lot of energy in the first place, and 2) carbohydrate metabolism slows due to depleted sugar levels within the cells, at which point...

the body turns to protein metabolism for energy. And where is the nearest supply of protein? In the muscular tissue already doing the work.

This actually happens a lot in marathon running, but can happen during any form of exercise in the spectrum if the intensity level is high enough for a prolonged period of time.

Understandably, your body is not generally relying on fats for energy during resistance training, but if you are working out at such an intensity that you are maintaining a heart rate around 80-85% of your max then it means that your body is working extremely hard to both deliver fuels (fats/carbs/proteins) to the cells to generate energy and removing metabolic wastes from your cells to prevent stalling of the metabolic process within the cells. That high a heart rate means that you body is working in an energy deficit, meaning that if it is prolonged, it will have to eventually turn to proteins to supplement its energy needs.