I have read that exercising over the target heart rate (85% of max. heart rate) is counter productive.

[bill1]

Is this because the body burns muscle rather than fat?

[Hidden]

Hi bill1,

My initial reaction is that the body "burning" muscle rather than fat is the sort of thing one would expect to happen to people on VLCDs, that is basically one of the risks of rapid weight loss.

I would have thought though that if you're on a properly healthy and nutritious diet, you would probably still have glycogen to burn, rather than muscle.

However, you can apparently trigger the body into breaking down muscle to keep itself going with other situations - including significant amounts of exertion.

But, I thought target heart rate (THR) was between 50% to 65% of maximum heart rate (MHR).

I thought the notion was that if you exercised at that rate - brisk walk with swinging the arms sort of thing - then 85% of the calories you burn will be from your fat storage.

As you up that heart rate, then the amount of calories burnt go up, but less of them are from fat and more from your glycogen stores.

Basically, I would have thought that you would only be getting into burning actual muscle after significantly long endurance type exercise, e.g. marathon running and similar, as by then your glycogen store (how the body stores the energy from carbohydrates) would probably be exhausted.

That's how I understand it, anyhow.

[bill1 in reply to Hidden]

Many thanks for a thoughtful and helpful answer. At 65, my exercise is brisk walking as you describe - mildly out of breath - as jogging puts my back into spasm and being still overweight I don't want to stress my knees.

My son has just given me a heart rate monitor and looking at the charts, my max heart rate should be 150 but I find that for significant portions of my exercise, my heart rate is between 140 and 150. Obviously I can reduce that by slowing down. So either my heart is dodgy (not according to my GP), the monitor is wrong or my max heart rate should be higher.

My present aim is to loose weight, fitness at the moment is a bonus. I just don't want to waste time exercising but not burning fat.

Anyway, many thanks for an interesting reply

Bill

[bunblebeaz]

I think that may be instead of burning the wrong sort body tissue, it means counter productive in that it can be damaging to your health.

Exercise has to be sustainable for a certain amount of time (ignoring HIIT, even so, this allows for rest periods).

I imagine that if you were to work out for 30 mins at 100% of max heart rate, your heart would not like it and repeated efforts would lead to heart attacks etc.

On the other hand I know people that have to work above the 85% as this level does not seem right for them, they don't break a sweat, or a light run sends them over the limit.

Not every one is the same and workout threshold is only a guide.

Do what feels right for you, and if it gets too hard stop, if its too easy, up the intensity.

[bill1]

Thanks bunblebeaz. That sounds a sensible and comprehensible approach. I am somewhat wary of one size fits all guidelines. If I were to lose weight to the "ideal" BMI, there'd be nowt left of me.

[Hidden in reply to bill1]

Hi bill 1,

When I started this weight loss journey the weight I am now (92.5 Kg) seemed a very, very long way off indeed. I reckon that as you get nearer to it, your "ideal" BMI won't seem so very unattainable at all.

The 'normal' band of BMI can span almost 3 stone in places. I'm sure there's room for everyone in there!

[bill1 in reply to Hidden]

Mmmmm. I've yoyo dieted for most of my (65) years but the weight I'm most comfortable at - and played vigorous sport at in my youth - is 2 stone higher than the middle of the BMI chart.

Like the bird that picks the crocodiles teeth......... I have grave doubts.

[NinjaC00M]

um... The key points to remember when it comes to calorie expediture are;

High intensity exercise leads to EPOC (higher metabolism for up to 2 hours after exercise)

Fat will only every be used as a fule source during aerobic exercise once imediate fule stores are depleated.

The body will generally not break down muscle as a fule source unless you have been starving yourself or eating at irregular intervals.

The reason HIIT has really taken off despite being taught for the last 5 years is number of people seeing results. A 10 minute HIIT session can burn as much or in most cases more than an hour gently jogging due to EPOC.

Also BMI is a really bad system to use much like weighing yourself, neither of these take into account body shape, bone density, muscle to fat ratios ect. You will be much better using your reflection to note differences in body shape or if you must used mesurement go for body fat % and limb circumfrences.

Appologies for the bad spelling, remember train as hard as you feel is comftable until it becomes a way of life then continue to push yourself and raise your goals. The only person standing between you and your goals is you =)

[bill1 in reply to NinjaC00M]

As I said above, I have grave doubts about the BMI chart. I used to play club rugby at 14.5stone but the BMI chart suggests that I should be around 11 stone. I'm not convinced

Lot of good sense in what you say. I shall have to look up HllT - never heard of it.

Thanks for the reply.

[OlsBean]

Loosely 65-70% of Max Heart Rate is optimum range for fat burning, you'll not a lot of fat burning programs on Gym Equipment such treadmills aim to keep you within this zone for this reason. At 70%-85% you tend burn more carbs but there are other factors at play and it's not an exact science. 85% + is not a zone you should regularly be exercising in but if in doubt ask your Doctor.