If only....

[Todd S]

...the last sentence of this write-up could be implanted into the brains of those still sold on "the fat burning zone".

"Because the use of glycogen is dependent on the relative intensity of exercise, as one gets relatively fitter more fat is burned at a given absolute exercise intensity and more glycogen will be spared allowing for top end energy reserves for that late-in-the-day attack and win."

http://www.saris.com/athletes/PermaLink,guid,6db7d592-53a6-4a3e-839b-93703a780ba8.aspx

[Pink]

...the last sentence of this write-up could be implanted into the brains of those still sold on "the fat burning zone".

"Because the use of glycogen is dependent on the relative intensity of exercise, as one gets relatively fitter more fat is burned at a given absolute exercise intensity and more glycogen will be spared allowing for top end energy reserves for that late-in-the-day attack and win."

http://www.saris.com/athletes/PermaLink,guid,6db7d592-53a6-4a3e-839b-93703a780ba8.aspx

Ah but if that happens, I'll have to find another use for my soapbox. I've actually had ladies bring me torn out pages of "Woman's World" to convince me that they don't need to break a sweat to lose weight. And they wonder why they are fat.:rolleyes:

[SpinBob]

...the last sentence of this write-up could be implanted into the brains of those still sold on "the fat burning zone".

"Because the use of glycogen is dependent on the relative intensity of exercise, as one gets relatively fitter more fat is burned at a given absolute exercise intensity and more glycogen will be spared allowing for top end energy reserves for that late-in-the-day attack and win."

http://www.saris.com/athletes/PermaLink,guid,6db7d592-53a6-4a3e-839b-93703a780ba8.aspxI think I understand what you're getting at Todd, but doesn't the operative concept here revolve around "as one gets relatively fitter?"

[Todd S]

Yup.

Being a fat burner/glycogen sparer is all about being fit and not about exercising at intensities that burn fat and spare glycogen. Train to maximize performance (fitness) and by definition you're training to minimize glycogen burning at all exercise intensities.

[SpinBob]

So you suggest that someone who isn't fit and overweight should focus on fitness and weight loss will follow?

[Todd S]

Yes provided they don't view their training as a license to eat.

I don't see fat burning/glycogen sparing really having all that much to do with weight loss (that's more related to maintaining a slightly negative Calorie balance). It's really only important during long events where bonking is a concern.

[like2bike]

I have struggled to get my head around this concept for so long, and I think maybe I've got it now.

There is no fat burning "zone" (especially during a 45-60 minute spinning class). Is you are focusing on using your fat stores for NRG instead of your glycogen stores, you're doing that purposefully because you are saving your gycs for a later need (like sprinting to the finish). Do I have it? Please? Do I? :(

[wh8sox]

What percentage of people in your classes are in the fit category? 50% ? Less?

For those unfit walking up to an eliptical machine where do they start?

I think for the fit folks the article applies, but for the general population, the question is how to get fit. Fitter is better, but if you aren't there yet the fat burning zone works..right?

[Pink]

What percentage of people in your classes are in the fit category? 50% ? Less?

It depends. In most of my classes, 90% are pretty fit. There's always a few who are just beginning the process. And I also teach a workshop 2x a year, where most are fairly unfit.

For those unfit walking up to an eliptical machine where do they start?

I think they should work at a level where they are challenged but able to hold the intensity for the length of the workout. 20 minutes or so. So the super unfit, will be moving very slowly. As they become more fit, they can increase the time and adjust the intensity. If they have a good handle on RPE, they should be able to manage their effort. And if they have medical clearance, I don't see any reason they can't push themselves a bit once they are comfortable with the movement (i.e. short spurts--intervals)

I think for the fit folks the article applies, but for the general population, the question is how to get fit. Fitter is better, but if you aren't there yet the fat burning zone works..right?

I guess. I think, in some ways, it's just semantics. If they are working at a level they are able to hold for 20 minutes or more, they are metabolizing a preponderance of fat calories.

Obviously, if I'm off-base, someone will set me straight and I'll continue to learn...

[Todd S]

I think Pink's got it right.

The reason we bother with HR monitors, RPE, and power meters is to standardize exercise intensity relative to each individual's fitness and performance capability. For an unfit individual, a low intensity effort or a hard threshold effort shouldn't feel all that different or be drastically different in terms of metabolic stress than the same relative effort for a fit individual even though the work being performed is drastically different.

The painfully easy effort for a fit individual could easily be a VO2max type interval for an overweight couch potato.

[Todd S]

I have struggled to get my head around this concept for so long, and I think maybe I've got it now.

There is no fat burning "zone" (especially during a 45-60 minute spinning class). Is you are focusing on using your fat stores for NRG instead of your glycogen stores, you're doing that purposefully because you are saving your gycs for a later need (like sprinting to the finish). Do I have it? Please? Do I? :(

Not exactly.

The greater the intensity (relative to your OWN fitness or performance capability) the more glycogen you burn.

Think of yourself in a spirited group ride with riders of your size and weight but of a variety of fitness levels. You all start and end at the same time so you've all done pretty much of an equivalent amount of work in the same amount of time. However, the fitter riders probably weren't really taxing their capabilities to any great extent, so the glycogen they burned on the ride was relatively low (it was a low intensity ride relative to their fitness level). The less fit riders, on the other hand, were maxed out most of the time just to keep up. Even though they used the same amount of energy as the fit riders they drew heavily on their glycogen stores since they were practically red-lined the whole way.

So fitness gives a rider two advantages:

1) Compared to a less fit rider, they can put more power to the pedals over a given time period (thus they burn more Calories over that time period if weight loss is a concern).

2) At lower absolute power outputs that would redline a less fit rider and put the less fit rider in a state where they're drawing heavily on glycogen stores, the fit rider is minimizing glycogen usage as they're working at a lower intensity relative to their own capabilities.

[Pink]

Now I've got a question, Todd...

If someone (fit or unfit) depletes their glycogen stores (bonks), when they are at rest -- can they replenish them w/o eating? Can stored fat be changed into glycogen?

I am thinking of a diabetic who must eat when they begin to go into insulin shock, but I don't know if it's as severe in an exercize scenario. Or is it al just a matter of degrees? Yes, I understand it could be dangerous (brain needing sugar and all) but I'm curious if the healthy body can right itself with its fat stores.

I'm also thinking of the person who equates a hard exercise session with a pig-out session afterwards (guilty as charged at times).

[wh8sox]

I think they should work at a level where they are challenged but able to hold the intensity for the length of the workout. 20 minutes or so. So the super unfit, will be moving very slowly. As they become more fit, they can increase the time and adjust the intensity. If they have a good handle on RPE, they should be able to manage their effort. And if they have medical clearance, I don't see any reason they can't push themselves a bit once they are comfortable with the movement (i.e. short spurts--intervals)



I guess. I think, in some ways, it's just semantics. If they are working at a level they are able to hold for 20 minutes or more, they are metabolizing a preponderance of fat calories.


Pink,

I think you are right..semantics or marketing, but burning a preponderance of fat cals--isn't that the fat burning zone?

I recently did a Josh T EEZ ride and was really challenged especially toward the end of the ride..I worked harder but in a different way than other classes. I guess that was the point..


This is one of my new years resolutions...On the subject of get fitter then you'll burn more fat...I struggle personally with developing muscle (upper and lower body), reducing body fat/weight, and endurance all at the same time. I don't view my goals as any different from other people's.

So for someone going to the gym to loose a few pounds and get leaner. Seems to me the first answer is to fix the diet, second step is to??? EEZ idc classes?

My example of why I think there is value in the term fat burning zone- DW (a idc newbie) recently attended one of my IEZ with all the pre-class warnings about taking things down a notch and not trying to do everything.She went bttw, she somehow did not get it(blame the messenger!).

[like2bike]

Not exactly.

The greater the intensity (relative to your OWN fitness or performance capability) the more glycogen you burn.

Think of yourself in a spirited group ride with riders of your size and weight but of a variety of fitness levels. You all start and end at the same time so you've all done pretty much of an equivalent amount of work in the same amount of time. However, the fitter riders probably weren't really taxing their capabilities to any great extent, so the glycogen they burned on the ride was relatively low (it was a low intensity ride relative to their fitness level). The less fit riders, on the other hand, were maxed out most of the time just to keep up. Even though they used the same amount of energy as the fit riders they drew heavily on their glycogen stores since they were practically red-lined the whole way.

So fitness gives a rider two advantages:

1) Compared to a less fit rider, they can put more power to the pedals over a given time period (thus they burn more Calories over that time period if weight loss is a concern).

2) At lower absolute power outputs that would redline a less fit rider and put the less fit rider in a state where they're drawing heavily on glycogen stores, the fit rider is minimizing glycogen usage as they're working at a lower intensity relative to their own capabilities.

OK let me try again. So if I am fit (and I am) and I am inline skating or cycling or whatever, rolling along, going at a pretty good clip but not going hard (but going hard enough to break a sweat and feel an increase in my RPE) and a skater or rider next to me is NOT fit, he/she is likely burning glycogen stores just to keep up with me, the fit person. While I am burning fat calories by doing what I'm going. Is that it?

Also, can you please define "power" (in this sense) for me? I think that will help solidify this in my head better.

Thank you Todd (and Pink and wh8sox and Bob for weighing in here. I'm not sure why I have such a brain fart going on about this concept but I think I'm getting it....)

[Todd S]

OK let me try again. So if I am fit (and I am) and I am inline skating or cycling or whatever, rolling along, going at a pretty good clip but not going hard (but going hard enough to break a sweat and feel an increase in my RPE) and a skater or rider next to me is NOT fit, he/she is likely burning glycogen stores just to keep up with me, the fit person. While I am burning fat calories by doing what I'm going. Is that it?


Yup.

Also, can you please define "power" (in this sense) for me? I think that will help solidify this in my head better.


Power to the pedals in watts which is directly proportional to Calories being burned.

[Pink]

Pink,

I think you are right..semantics or marketing, but burning a preponderance of fat cals--isn't that the fat burning zone?

Yes, if you need to call it something. Basically, you are working below threshold, taking in enough oxygen to support & sustain the effort -- therefore burning a larger percentage of your calories as fat. So, yes, you can call it "the fat burning zone." I think where I have trouble with it is it somehow gets sold as 'work comfortable & burn fat.' They forget to say that in order to burn enough fat to make a difference (especially vis-a-vis weight loss), you have to do it for much more time than most people can fit into their schedules.

I recently did a Josh T EEZ ride and was really challenged especially toward the end of the ride..I worked harder but in a different way than other classes. I guess that was the point..


This is one of my new years resolutions...On the subject of get fitter then you'll burn more fat...I struggle personally with developing muscle (upper and lower body), reducing body fat/weight, and endurance all at the same time. I don't view my goals as any different from other people's.

So for someone going to the gym to loose a few pounds and get leaner. Seems to me the first answer is to fix the diet, second step is to??? EEZ idc classes?

Yes, agreed. The first step is diet control. The second step (at least for me) is maintaining muscle mass -- lifting enough weight to make a difference. That's different that doing the same 5 lbs biceps curls year in and year out.

My example of why I think there is value in the term fat burning zone- DW (a idc newbie) recently attended one of my IEZ with all the pre-class warnings about taking things down a notch and not trying to do everything.She went bttw, she somehow did not get it(blame the messenger!).

Again, this is where RPE comes into play.

[Swiss Miss]

Exactly. Identifying RPE is right up there with monitoring heart rate and power. I wish HR monitors didn't come with an option to view heart rate as a percentage b/c I see riders so focused on the 75%, 80%, 85%...and so on. They have become slaves to this percentage without even knowing if: a) it's accurate for them b) how they should feel relative to that zone. I rarely teach with percentages anymore. I give them a few zones to work with and we talk RPE (since I don't have to luxury of power meters). If they want to learn how fit they are becoming, they need to look at the actual bpm's on their monitors and start to compare over a range of time how those numbers change and adapt at different intensities as they become more fit, and threshold becomes closer to max- giving them a bigger range to work with.

I still struggle with labeling any specific zone a "fat burning zone" because I think it can be misleading to some people. Yet, I believe there is an obvious advantage to working sub threhold in order to train the body to utilize fat and spare glygogen. Unless they've been VO2 tested, how do we know where they burn the most fat? We don't. Everyone is different. That's when I call on my friend Danielle and send them her way!:D

[Todd S]

If they want to learn how fit they are becoming, they need to look at the actual bpm's on their monitors and start to compare over a range of time how those numbers change and adapt at different intensities as they become more fit, and threshold becomes closer to max- giving them a bigger range to work with.

I'd be careful with that. HR and fitness aren't related. Remember, HR is a proxy for cardiac output but their relationship is highly variable due to variations in stroke volume.

Yet, I believe there is an obvious advantage to working sub threhold in order to train the body to utilize fat and spare glygogen.

This is a fallacy that keeps getting perpetuated. Training at intensities where your body is utilizing fat and sparing glycogen does not train your body to better utilize fat and spare glycogen. Adaptation occurs with a specific overload of some sort to the targeted metabolic system. Your body therefore becomes more efficient at sparing glycogen and using fat through an adaptation induced by stressing your aerobic pathways to unaccustomed levels through either intensity or duration or some combination of both. Low intensities are not the most efficient way to apply that adaptive stress to your aerobic energy system.

[like2bike]

Crap! I'm confused again!

[Todd S]

Think of it this way.

If you're running almost exclusively on fat, you're not stressing your aerobic system. It's comfortably on cruise control. Stress your aerobic system in some way through training and when you go back to cruise control type intensities you'll either be burning even less glycogen or your new cruise control intensity will be a little faster and more powerful at the same perceived level of effort.

[wh8sox]

We may be talking 2 different things. My view is that it is hard to explain sub- threshold work to the un-fit.(I know RPE...that is still a hard sell to someone with little body awareness). Fat burning zone is a dumbed down term that people get.

I think todd is saying get fit and then all zones are fat burning zones (when you have single digit body fat)

[Swiss Miss]

Damn, I still don't know how to post original messages!

Anyway, Todd said: I'd be careful with that. HR and fitness aren't related. Remember, HR is a proxy for cardiac output but their relationship is highly variable due to variations in stroke volume.

What I was trying to state was that over time, as a person becomes more fit through overload to their aerobic system, their heart rate zones will change in that their perceived exertion will feel easier at the same heart rate that used to feel hard. So isn't that showing a relationship between heart rate and fitness? Especially since a more fit person will often decrease resting heart rate as they become more fit. I'm just curious... loving the discussion and wanting to learn more!

[Todd S]

I think todd is saying get fit and then all zones are fat burning zones (when you have single digit body fat)

Not really.

When you're fit your moderate intensity zone will allow you to outperform a less fit person who's maxed out. Fit or unfit, fat or lean, when you're working at an intensity that's near, at, or above an intensity you can sustain there's going to be a lot of glycogen burning going on. But you're also burning more total calories (which will contribute to bodyfat loss) and stressing your aerobic energy system in such a way that positive fitness adaptations will take place and therefore make you a better fat burner at all intensities.

[Pink]

We may be talking 2 different things. My view is that it is hard to explain sub- threshold work to the un-fit.(I know RPE...that is still a hard sell to someone with little body awareness). Fat burning zone is a dumbed down term that people get.

I think todd is saying get fit and then all zones are fat burning zones (when you have single digit body fat)

Actually, I haven't had trouble with this. I tell them they that although their breath may be weighted, they should be able to talk in sentences. I tell them to work up to the point where they can say "Mary had a little lamb." <pause for breath> "Whose fleece was white as snow." <breath> If they can only say, "Mary had a" <gasp> "little lamb" <gasp>, they are working too hard. However, if I am doing intervals, I'll tell them I want them at that last point during the interval but they should recover down to easy talking. And they are not to start the next interval until they can. I find this works pretty well.

[wh8sox]

Actually, I haven't had trouble with this. I tell them they that although their breath may be weighted, they should be able to talk in sentences. I tell them to work up to the point where they can say "Mary had a little lamb." <pause for breath> "Whose fleece was white as snow." <breath> If they can only say, "Mary had a" <gasp> "little lamb" <gasp>, they are working too hard. However, if I am doing intervals, I'll tell them I want them at that last point during the interval but they should recover down to easy talking. And they are not to start the next interval until they can. I find this works pretty well.


I guess I meant that it is hard to explain the benefits of sub-threshold work to ....wait I am not sure of the benefits anymore....remind me again Todd.

No really, I think I got Todd's point from his "fitness adaptations" post, and I agree with that from a training and getting better at burning fat perspective.

So why not just go till just before we bonk in each work out? and train with the goal of moving the bonk threshold further and further out?

[like2bike]

Actually, I haven't had trouble with this. I tell them they that although their breath may be weighted, they should be able to talk in sentences. I tell them to work up to the point where they can say "Mary had a little lamb." <pause for breath> "Whose fleece was white as snow." <breath> If they can only say, "Mary had a" <gasp> "little lamb" <gasp>, they are working too hard. However, if I am doing intervals, I'll tell them I want them at that last point during the interval but they should recover down to easy talking. And they are not to start the next interval until they can. I find this works pretty well.


GOLD. SHEER GOLD.

[wh8sox]

Actually, I haven't had trouble with this. I tell them they that although their breath may be weighted, they should be able to talk in sentences. I tell them to work up to the point where they can say "Mary had a little lamb." <pause for breath> "Whose fleece was white as snow." <breath> If they can only say, "Mary had a" <gasp> "little lamb" <gasp>, they are working too hard. However, if I am doing intervals, I'll tell them I want them at that last point during the interval but they should recover down to easy talking. And they are not to start the next interval until they can. I find this works pretty well.

I agree that this is a good one! Thanks

[NJspin]

Guessing I'll never be there .. I can't get my BF to drop below 17% no matter what I do.... and I am no way FAT after teaching 4-6 classes a week for three years now. :) OH WELL.. so be it. I think todd is saying get fit and then all zones are fat burning zones (when you have single digit body fat)

[wh8sox]

Guessing I'll never be there .. I can't get my BF to drop below 17% no matter what I do.... and I am no way FAT after teaching 4-6 classes a week for three years now. :) OH WELL.. so be it.

Blame the measurement/person doing the pinching!!

[veespin]

Now I've got a question, Todd...

If someone (fit or unfit) depletes their glycogen stores (bonks), when they are at rest -- can they replenish them w/o eating? Can stored fat be changed into glycogen?

I am thinking of a diabetic who must eat when they begin to go into insulin shock, but I don't know if it's as severe in an exercize scenario. Or is it al just a matter of degrees? Yes, I understand it could be dangerous (brain needing sugar and all) but I'm curious if the healthy body can right itself with its fat stores.
.

A bit late with this reply, Pink but here goes.

The short answer is yes.....but I fancy that someone who's bonked would be lying at the side of the road for a fair amount of time before the body's biochemical pathways set them right.

When stored triglycerides are mobilised as a source of energy, they split into free fatty acids and glycerol. Only the glycerol molecules can be converted to glucose by the liver, along with amino acids from protein breakdown. There's a rate limit to this mechanism as a source of energy and I doubt it'd kick in quickly enough to allow you to hop back on the bike and join up with your cronies or provide enough ATPs to allow for a decent amount of work.

In addition, if carbohydrate sources are limited, energy production from fatty acids takes a bit of a circuitous route via ketone production rather than use of the Kreb's cycle. Again, there's a rate limiter here as this isn't a particularly efficient or quick energy delivery system but is really designed as a pretty elegant way for the body to function during starvation.

Vivienne

[Pink]

A bit late with this reply, Pink but here goes.

The short answer is yes.....but I fancy that someone who's bonked would be lying at the side of the road for a fair amount of time before the body's biochemical pathways set them right.

When stored triglycerides are mobilised as a source of energy, they split into free fatty acids and glycerol. Only the glycerol molecules can be converted to glucose by the liver, along with amino acids from protein breakdown. There's a rate limit to this mechanism as a source of energy and I doubt it'd kick in quickly enough to allow you to hop back on the bike and join up with your cronies or provide enough ATPs to allow for a decent amount of work.

In addition, if carbohydrate sources are limited, energy production from fatty acids takes a bit of a circuitous route via ketone production rather than use of the Kreb's cycle. Again, there's a rate limiter here as this isn't a particularly efficient or quick energy delivery system but is really designed as a pretty elegant way for the body to function during starvation.

Vivienne

Vivienne, thanks so much to the wonderful explanation. I know I've experienced this when Mr. P. (who's a Type I Diabetic) has gotten shocky. I guess I was wondering if you weren't in danger of insulin shock (just feeling a little shakey), whether the body could recover without eating...and how effective this would be as a fat burner. (Not smart, mind you, but effective.)

And, btw, where have you been? It's good to see you!

[veespin]

I guess I was wondering if you weren't in danger of insulin shock (just feeling a little shakey), whether the body could recover without eating...and how effective this would be as a fat burner. (Not smart, mind you, but effective.)

And, btw, where have you been? It's good to see you!


Well, the low carb enthusiasts will assert that it's a marvellous way to lose weight....depleting glycogen with an ultra low carb, ketogenic diet (Atkins "induction", for example) and "forcing" the body to burn fat.

There's a biochemically plausible side to this notion as, when the body starts to manufacture ketones as a route to ATP production, there's a bit of calorie "wastage" as acetone (one of the ketone bodies that's produced) isn't metabolically active and spills over into the urine or is excreted via the lungs. However, it's a fairly small % of daily energy expenditure all told so doesn'[t contribute much to maintaining a negative calorie balance.

Another problem with a ketogenic diet (or bonking) as a weight loss tool is that using fat as a primary source of fuel is a bit self limiting. Lipolysis as a process is a complex set of enzyme reactions and is correspondingly quite slow....to the extent that you just can't fuel high intensity exercise with it alone.

High intensity=greater fast twitch fiber recruitment.....you really do need glucose/glycogen to fuel high intensity exercise no matter what the low carbers would have you believe.

As to where I've been......right here but I've been on roller skates for most of the Summer (some retirement this is turning out to be!!) Over the course af a few weeks we closed finally on the sale of our home on LI and also the little condo we bought while Geri was up at vet school in Ithaca/had her "graduation" from her internship at the AMC/moved the last of my goods and chattels from LI up to Boston, along with the contents of Geri's apartment in NYC/moved Geri into her new apartment in Boston (she loves our home but it's not enough in the hub of things for her to want to live at home) The smoke from all that activity is starting to clear so I'm catching up on all my boards.

Vivienne