Fitbit's 150 Billion Hours Of Heart Data Reveal Secrets About Health

yerrag

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lol you implying the rest is false?
If I recall right from the book, it's the part about burning more fat when running at a low heart rate that she disproved. I'll have to find that book and go through it again. I think she was saying it makes no difference what the heart rate is.

Even now, I don't see why running at a low heart rate makes you burn more fat than carbs, in an absolute or relative sense. And by 'you' I refer to a healthy euthyroid (normal thyroid) person with good blood sugar control. But if a person has poor glucose uptake to his cells, he would always have to rely on fatty oxidation as glucose oxidation would be insufficient for his energy needs for running. Still, what he burns would still be independent of his heart rate.
 

nerfherder

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No that can't be right. I hadn't mentioned fat when you implied my post was false. Were you thinking of someone else? Or was there something else you objected to?
 

yerrag

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No that can't be right. I hadn't mentioned fat when you implied my post was false. Were you thinking of someone else? Or was there something else you objected to?

I checked the book as I still have it. It questioned both the formula used for calculating max heart rate (220 - age), as well as the idea that more fat is burned when you run at a low heart rate. Polar uses the max heart rate formula, as well as many doctors, and it is a really stupid formula.

But you had mentioned fat:

At lower heart rates you burn mostly fat. At higher ones mostly sugar. There's a transition. They measure a crossover point where it is 50:50. Another thread here pointed to an article where some hiker measured changes in his ratios from hiking for a month. You can see the changes and ratios at the link. His crossover point went from 153 to 168. Even at 110bpm he went from 34% carbohydrate burning to 9%.

And what you say is pretty much accepted by the running community, and I believe it is also espoused by Polar. Given that Polar propagated a myth with how it maximum heart rate is calculated, it makes me leery of accepting the idea that it helps propagate on fat burning zones being at low heart rate. I'm not expecting you to know the answer, but if you do, what is the basis for this idea?

I mean, what is it about running at a low heart rate that makes it burn more fat than carbs? On this basis, are we to say when we walk, we burn more fat as well? And how about when we just lie on a couch watching TV, do we also burn more fat?

Looking at it from a Peat standpoint, wouldn't euthyroid people with good blood glucose control be given to burn more carbohydrates? And wouldn't people with plenty of PUFA (free fatty acids) in the blood be more likely to burn fats? Wouldn't it be reasonable to say that the heart rate would have less bearing on whether fat or sugar is burned, than the metabolic makeup of the person would?
 
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nerfherder

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OK this is getting weird. I talked about HR in two posts. Then you made the comment I am questioning (3:13pm). I had made _no_mention_of_fat_. You're copy/pasting from what I wrote *after* your comment (3:44pm). What were you commenting on? You didn't time travel.

You went to the effort of copy/pasting from a later post in order to do what? The whole thread is online for all to see.

I'd love to chat about fat but this is nuts.
 

yerrag

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OK this is getting weird. I talked about HR in two posts. Then you made the comment I am questioning (3:13pm). I had made _no_mention_of_fat_. You're copy/pasting from what I wrote *after* your comment (3:44pm). What were you commenting on? You didn't time travel.

You went to the effort of copy/pasting from a later post in order to do what? The whole thread is online for all to see.

I'd love to chat about fat but this is nuts.
Can't you get over that? Seems like you're getting stuck on this 'weird' bit and unable to proceed.
 

nerfherder

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lol it wasn't me that was copy pasting from the future.

You mention a formula 220 - age which at my running HR limit of 124bps would make me 96 years old. I look awesome for 96. That's strawman 1.

You also denigrate what Polar says and like who gives a rat's **** what Polar says. That's a strawman 2.

"Fat burning zones" is another thing I did not mention and do not care about. Strawman 3.

Did you see the data in the link you copy/pasted? It shows a couple of tests and the subject fat % and carb % at 110bpm, at 145bpm and the crossover point where it would be 50/50. They run the subject on a treadmill and analyse the breathing output. They've been doing this for a while but it is getting more popular now commercial units are cheaper. At those three different heart rates you are getting different percentages of energy coming from fat. Here, I'll put in a copy for you so you don't have to look at the other forum page:

metabolic-efficiency-chart.jpg


He burns a higher percentage of carbs as he increases exercise intensity. After his hike he burns 9% at 110bpm then 30% at 145bpm then 50% at 168bpm. Are you doubting these numbers? The equipment is completely bogus?

This data is interesting to me because it shows training effects. The hiker burned a higher % of fat at a given heart rate after hiking for a month than he did beforehand.

I'm not sure what you are saying is false here. This doesn't seem controversial. Your fat metabolism can't ramp up like the carb metabolism can and the carbs take over as intensity increases.
 

yerrag

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You mention a formula 220 - age which at my running HR limit of 124bps would make me 96 years old. I look awesome for 96.

Well, for a 51yr old, you do like to conflate things:

Some of us run/cycle at lower heart rates (e.g. I limit mine to 124 bpm) in order to increase heart efficiency (i.e. swept volume). This training does lower your RHR by counteracting the effects of the first, fitness-related process. Then the RPF focuses on using diet to improve metabolism and counteract the effects of the second, aging-related process.

24 is simply the number from Maffetone's system for a 51yo. I could do 129 but running/riding has been on and off too much so I take off the extra 5bpm to be safe.

You are referring to Maffetone's maximum training heart rate. The 220-age formula of Haskell is maximum heart rate (not just training). And I was making criticism of the way Polar has misapplied Haskell's formula and used it in educating people on determining the safe maximum heart rate for running. I don't know what the big deal is.
You also denigrate what Polar says and like who gives a rat's **** what Polar says. That's a strawman 2.

No strawman here. Doesn't make what you're saying any less true.
"Fat burning zones" is another thing I did not mention and do not care about. Strawman 3.
Being downright fussy here. What did you say about fat burning and lower heart rate? Did I miss something?

Did you see the data in the link you copy/pasted? It shows a couple of tests and the subject fat % and carb % at 110bpm, at 145bpm and the crossover point where it would be 50/50. They run the subject on a treadmill and analyse the breathing output. They've been doing this for a while but it is getting more popular now commercial units are cheaper. At those three different heart rates you are getting different percentages of energy coming from fat. Here, I'll put in a copy for you so you don't have to look at the other forum page:

metabolic-efficiency-chart.jpg


He burns a higher percentage of carbs as he increases exercise intensity. After his hike he burns 9% at 110bpm then 30% at 145bpm then 50% at 168bpm. Are you doubting these numbers? The equipment is completely bogus?

This data is interesting to me because it shows training effects. The hiker burned a higher % of fat at a given heart rate after hiking for a month than he did beforehand.

I'm not sure what you are saying is false here. This doesn't seem controversial. Your fat metabolism can't ramp up like the carb metabolism can and the carbs take over as intensity increases.

I'm questioning the basis for his results. I'm questioning whether the results are representative of a healthy euthyroid individual who has excellent blood glucose regulation (neither diabetic nor hyperglycemic). I'm questioning what equipment he uses to determine how much fat and how much carbs are being burned. I'm doing this because it isn't consistent with what I know about 0xidative metabolism in a healthy individual, who would be burning carbohydrates more than fats at rest, at low level running rates, as well as at high level running rates. Fat oxidation, I believe, in such an individual only kicks in greatly when his glycogen reserves run out.

What the example you showed brings up is an example of one person. It shows results that I can question, as to the device used to measure fat and carb burning and as to its basis for making the calculations. Just because he was tested at a well-known facility with standard equipment means little to me. It comes down to whether the basis for measuring and computing the results are sound. I don't give a rat's **** about that lab being recognized or certified or has ISO-9001 rating, which are not of much use as compared to the reliability of the methodology and science behind the measurements and computations.
 

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