How are people burning so many cals?
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You are making the common mistake that heart rate has anything to do directly with burning calories. It does not.
Simple physics dictates it takes X number of joules to move an object of Y grams a distance of Z meters. That will never change. Where things get complicated is how you move the object and what it is. If it is a giant block of wood and you are dragging it on the ground you will have to overcome friction. If you put the block on wheels you have less friction to deal with and it takes less energy. In a theoretical frictionless system you can calculate the exact amount of energy needed to accelerate the object and then decelerate it before it gets where you want it.
Since we are not in a frictionless environment, there will be efficiency losses - these can be calculated as well. You will come up with a number that actually is power (joules/second) required to move the item.
The human body produces power using muscles to drive the object forward. In this case we aren't talking about a block of wood, but our own selves. There is an efficiency loss in that not every watt you produce is used in moving the body forward. The body itself is inefficient, among other things (the number for cycling is about 25%. Meaning 25% of the power you produce is actually used to move you forward. I am not sure what that number is for running).
OK why are we talking about this? Well, it comes down to HOW the body produces power. When your muscles work, they consume three things, water, oxygen and glucose (I am being simple here, let's not complicate things with talk of Krebs cycles, ATP/ADP, etc ). Glucose is the actual fuel - think of it like gasoline in the car. The muscle also needs water and oxygen to utilize the energy in the glucose. If asked to work harder, the muscle consumes more glucose (fuel...ie CALORIES), and consequently needs more water and more oxygen. Oxygen is carried to the muscles via red blood cells. So when the muscle needs more oxygen, how does it get it? Well it comes from blood. If it needs more blood, the heart has to work harder to provide that oxygen, and to do that it speeds up. Aside from blood pressure conditions, the heart doesn't pump any HARDER to get blood flowing around the body, rather it goes faster.
So... correlation: heart rate rises when the body is producing more power. If the muscles are burning more calories to move, then the heart rate will rise to provide oxygen to accommodate the consumption of fuel. So as you can see your higher heart rate is an indicator that fuel is being consumed elsewhere in the body, but it is not a direct correlation. There are algorithms (linked above by a kind person) that can somewhat match the general correlation curve of calories burned to heart rate, but it is never exact because it is simply that - a correlation, not a causation. Your elevated heart rate is not what is burning calories, rather it is an indicator that calories are being burned somewhere else.
If I just stipulate that everybody here is smarter than me can we dispense with all the nonsense?- The mass is the same, namely me. In the second run, six months later, I have enough rocks in my pockets to equal the weight of the less fit me. There are no blocks; no wheels.
- Friction; Lets assume equal barometric pressure and can we agree the bulge in my pockets are insignificant to friction?
- We agree, I think, that the only significant difference is in the
stated and measurable variables is the heart rate.
Like you say, muscles consume three things and only two of them matter for this discussion.- water
- oxygen
- glucose
Some things that have not been stated and are not measurable by the tools available to me, changed for the better during the 6 months of hypothetical training. Taken together they can loosely be called fitness level. Two of them are:- The oxygen delivery (pulmonary) system improved. I can get more oxygen to the muscles.
- There are more muscles cells, which is to say, I'm stronger.
Your final paragraph has no bearing to the question at hand. Causation versus correlation? Nobody thinks the heart is actually moving the mass, me that is. Nor is the heart, ten ounces of muscle, burning more than an insignificant percentage of the glucose.
As far as I can tell no light has been shed on the original question. Does this new improved, more fit body with more muscle that is better oxygenated move x mass y distance more efficiently, that is with less fuel (glucose), that the less efficient (unfit) body did six months ago.
Those that say it takes z joules to move x mass y distance and that's just physics are missing the point. We're not measuring joules, we're measuring calories from glucose. Two cars both weigh exactly 3000 lbs. It takes the exact same amount of energy to move them 1 mile. Car A gets 30 mpg. Car B gets 20. The one with the more efficient engine (more fit body) moves that 3000 lb car (my 250 lb body) one mile with less gas (glucose or calories).
So I don't claim to know the answer for sure. My mind is open but common sense seems to point toward the more efficient body needing less fuel to accomplish the same work. If I don't stop typing now I can feel a snark coming on.0 -
The question you are asking is not a simple one to answer.
You missed my point. Heart rate is a proxy for work completed by muscles. It is a symptom. Your body is producing power. It needs oxygen to produce that power. Your heart rate rises to meet the need. The power produced is the variable here, not the heart rate. This is why heart rate can only be an approximation.
If you are 150lbs and wearing a 100lb vest running 10 minute miles for 10 miles, it still won't correlate one-to-one with the 250lbs running 10 minute miles for 10 miles. The body has its own inefficiencies. The weight vest is all 100% inactive dead weight. The 250lb guy is going to have much more living, functioning muscle than the 150lb guy. Sure he has a lot of fat too but even fat cells are alive and consume energy.
The amount of actual energy expended to move both people will be the same, yes. But that is actual energy output into the earth in the form of feet pushing and getting an equal-but-opposite reaction. The amount of energy each body burned to produce that energy into the ground is going to be different. Even if you bring heart rate into the mix, all you have now is a secondary variable that is not necessarily directly correlating to power output. Some people are more efficient than others. Some people are more efficient when they are lighter than when they were heavier. Some people's musculature can handle the 100lb weight vest and others can't.
You do realize that calories and joules are both SI units of measurement for energy right? There are 4.18 joules per calorie. It is a direct conversion.0 -
I know a lot of people don't agree with HRMs but for me it works - my figures aren't off the MFP calculations and I usually subtract 100 calories from the figure to compensate for any discrepancies. I find I can burn up to 800 calories an hour in some classes (Body Combat and Box Fit are my highest calorie burners) and as low as 200 calories if I'm just having a weight session in the gym. I can always tell the difference though - in my high calorie burning classes I'm literately dropping with sweat and as red as a beetroot so I'd be surprised if I wasn't burning 600+ calories in the hour!
Weight is also a factor - a heavier person will burn more calories doing the same exercise as a lighter person.
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Work = Force x Distance. Someone with more mass will burn more calories going the same DISTANCE as you. Calculations are all estimates for calories burned even with heart rates etc. Take it all with a grain of salt.
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insaneteabag wrote: »I have a Polar heart rate monitor which calculates how many calories I'm burning - I can burn up to 800 calories an hour in some classes (Body Combat and Box Fit are my highest calorie burners) and as low as 200 calories if I'm just having a weight session in the gym. I can always tell the difference though - in my high calorie burning classes I'm literately dropping with sweat and as red as a beetroot!
Weight is also a factor - a heavier person will burn more calories doing the same exercise as a lighter person.
If you really want to know how many calories you're burning maybe invest in a HRM
None of this is in dispute... but the whole argument here is that HRMs are still to be taken with a grain of salt. They are still not as accurate as we would like. This is because they are not a tool to measure calorie counts at all. They simply measure heart rate. There is an indirect correlation that can be made between heart rate and work completed, but it is not exact.0 -
What we have here is a case of proof by assertion.
I'm finished with it.0 -
Runnermadre wrote: »brianpperkins wrote: »Runnermadre wrote: »Seems like there is a lot of negativity towards using an HRM to count calories burned, but I lost over 30 pounds over the course of 5 months using data from the HRM AND eating back those calories. So...
Some people accept the limitations of HRMs when it comes to caloric estimations. They are not calorie counters, period.
Anecdotes are not a substitute for science.
Maybe I'm not understanding what you mean... I'm not saying that you will get 100% accurate data for calories burned from an HRM, but that a good one will give you pretty good information. I use mine to pay attention to my zones as well as to track calories burned. When I first started losing, I would burn a lot of calories, but as I lost and became more conditioned, my workouts burned less. This would be the result of moving less mass and muscles becoming more efficient as they are more toned. Of course, it would stand to reason that I would be burning more calories at rest, so long as I was building muscle. Sometimes I would get a higher burn than what MFP shows, and sometimes less - because the HRM uses my personal information. MFP is not using my personal information, fitness level, etcetera, so it would make sense that an HRM would be far more accurate. It's also worth noting that I used it for every activity (I run, lift, circuit train, walk, and did some swimming for a time). There are also formulas you can use (using heart rate) to calculate calories burned. Still, nothing is going to give you information accurate to the calorie. I'm just not sure what the big deal is. Let's say it's accurate within 50 or even 100 calories. I tend to think 50 is more realistic, but either way, it's not going to totally derail someone's progress if they are carefully portioning and logging their food as well. My point is that it's a great tool, and I feel like it's silly to discourage someone from using it in that way.
You start here with an admission that they are not accurate ... make several assumptions ... then try to justify those assumptions based upon opinion and feelings.
HRM manufacturers concede that the devices are not accurate for lifting and circuits if you bother to read the science behind their products. There isn't a relationship between HR and anaerobic activity that they and circuits and intervals create effort/HR mismatches that result in incorrect numbers.
The devices are great tools for tracking cardiac response to stresses. They are not calorie counters. In the most simple terms possible, a HRM counts heart beats then plugs that number into a formula to ESTIMATE calories. Those formulae only hold up for a narrow range of moderate or higher intensity steady state cardio activities ... not walking, yoga, lifting, intervals, circuits, dance, etc. People using a higher end HRM and participating in one of the activities the formulae hold up best for ... running, cycling, rowing ... the devices can come close. The commonly cited low end HRMs used in activities beyond the steady state cardio result in gross inaccuracies that fill MFP's forum.
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I'm usually in the 200-250 range for a cardio session, then my lifting and stretching after. I don't think I've ever hit 500 in one workout, but I'll bet my husband does if he plays competitive indoor soccer for an hour.0
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I don't eat back exercise calories, because I'm doing a TDEE approach instead, but I'm training for a triathlon and half marathon right now, so when I bike 15 miles at 18 mph and follow it up with a 10 mile run (at ~10:30/mile), I'd venture to say I wouldn't be surprised if the 1000+ estimates I get are right.0
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Hey,
Not sure why people get so worked up by what calories others are burning.
On a 10k run I burn 820 calories. Im 182 pounds and have a pace of approximately 9.45 mins/mile. I use a HRM and my heart rate averages 158 over the 10k run. Some of you will be shaking your head right now but guess what i'm loosing weight at approxmately the rate MFP calculates and so far have lost close to 30lbs and dropped from 23% body fat to 16%.
During insanity, max 30 etc over the 30 minute cardio session I burn approxametly 320 calories.
I've had a few ppl scoff at my calorie burnt figures but the results speak for themselves :-) and to be quite frank I don't care if others don't believe me.
Shaun.0 -
moraiwebird wrote: »I don't eat back exercise calories, because I'm doing a TDEE approach instead, but I'm training for a triathlon and half marathon right now, so when I bike 15 miles at 18 mph and follow it up with a 10 mile run (at ~10:30/mile), I'd venture to say I wouldn't be surprised if the 1000+ estimates I get are right.
The irony is that the fitter you are, as a general rule, the better the HRM method approximates reality. In fact if you get fit enough, the error can go the other way, and you start flirting with *under*-estimates. Since you can go those distances, you are definitely fit enough to fit in the pocket.
The sad thing is that the people who most need realistic burn numbers - those who are heavy and unfit and struggling to improve - are the ones who get the most screwed up, surrealistically over-estimated numbers. And they're the ones in most psychologically vulnerable place, leaving them most susceptible to imprinting.
Those people are IMO being intentionally taken advantage of by the gadget-makers and their bull**** marketing.
They are no better than the likes of Dr. Oz and his ilk.
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When you see HUGE burns nearing the 1000 range, the answer would be... they're not burning that many cals.
It really depends on weight and height. But, is better to underestimate, than to overestimate your burn and eat back more than you should.
I average 6-7 hrs. of cardio a week, my garmin 200 estimates 7000+ calories..definitely wrong. I don't eat back all the calories and I still lose 2-3 pounds a week.
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MeanderingMammal wrote: »3dogsrunning wrote: »jenniferinfl wrote: »My Polar HRM said I burned 415 calories for my 5k walk this morning.
You can't use an HRM for activity like that and expect accurate numbers. The only way to get that burn on that distance is to weigh 450 pounds. Since you're around 200 pounds, that's a 100%+ over-estimate!
There really needs to be a sticky for HRMs....
Why not? Walking fast gets your heart rate up. I mean, I'm confused... can't use HRMs for intervals, can't use HRMs for lifting, can't use HRMs for steady cardio... then why bother with HRMs at all?
450 calories for 3.5 miles doesn't seem that crazy for a 200 pounds person, if she's walking fast, especially if there are hills etc.
The algorithms are based on steady state moderate intensity cardio. I can't remember the exact definitions but I do not believe walking would fall under that.
But to your other point - why bother using them at all - for heart rate training. Hrms were meant for use as that. They are not calorie counters. They can give estimates but their degree of accuracy will strongly depend on how they are used.
This is why it bothers me so much when people tell new people they need to get a HRM.
One wonders what delicate flower sees this as abusive enough to report it.
Seems that said delicate flower was delicate enough to flag me for abuse as well.
How precious...0 -
juliah1234 wrote: »3) Steady state cardio kills calories while you are working out but stops as soon as your done. HIIT cardio creates an O2 deficit that kills calories during and after your workout. Strength training, like HIIT, kills fewer calories during the workout but uses calories like carzy to rebuild muscle.
Excess Post-exercise Oxygen Consumption is about 4-6% in steady state situations, so it still happens. In true HIIT, noting that most people claiming to do HIIT on hese boards aren't really, is about 8-10%.
A smaller percentage of a larger number is generally going to be greater than a marginally higher percentage of a small number.
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brianpperkins wrote: »3.5 miles * 200 lbs * .3 = 210 calories ... a rough net expenditure based on a study reported in Runner's World.
Also consistent with MET - a 3mph-ish walk on level ground has a net MET of 2.5, so ~220-ish.
All in the same ball park located a long way from 400+
Ok so how do you figure out the net MET of an exercise then?
Anyway, if I burn 200 calories at 130 pounds in 50 minutes of walking at 4mph, I can't imagine that a 200 pound person wouldn't burn at least 50% more in one hour...
It scales roughly linearly with weight - so if that 200 pounder could cover the same distance in the same time, they would indeed burn 50% more. But realize the implications of this - to actually do this, the 200 pounder needs to be "50%" fitter than the 130 pounder. So we're no longer talking about two people at the same level of fitness.
At the same level of fitness, the heavier person will not be able to complete the same distance in a similar time frame, so it will take them that much longer to get to the same burn.It seems you all are saying that it's impossible but are pulling numbers out of nowhere.
Never said impossible - said most dieters weren't doing what they thought they were doing. At 250 pounds I was able to burn 1000 calories - but I had to run 10k to do it, which at 250 pounds let me tell you that is a **** ton of work. It takes significant (weight-adjusted) cardio capacity to pull that off in an hour.
Moving to Zumba or Jillian or any other interval-y thing, there was no way I could burn the same number of calories, because the interval-y nature of those workouts shift the balance towards anaerobic activity, and anaerobic capacity is lower than aerobic capacity (ie, you can't sprint as far as you can jog).
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[*] with an improved fitness level, I can strap on enough weight to equal 250 lbs and burn the same amount of calories going 1.5 miles in 30 min, even if my heart rate only averages 110 beats per minute.
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Do I understand you correctly?
Yes. The heart has become stronger and an increased volume of oxygen is moved through the system with each stroke. The oxygen is used to burn the fuel used, so fewer heart beats gives the same volume of oxygen to expend the energy.0 -
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MeanderingMammal wrote: »
Even basic science doesn't play well on MFP.0 -
I have this quote snippet, can't seem to find the science-y paper I pulled it from...several people have touched on this...O2 uptake and metabolic heat production are often proportional and the demonstration of this was a tremendous scientific achievement. This proportionality however is only found in adult, non-diseased subjects residing in a temperate environment, and those resting or engaged in light to moderate exercise.It must be noted that under certain conditions metabolic heat production can exceed O2 uptake. The potential error of using an O2-only measurement to interpret the energy expenditure of heavy to severe exercise justifies the need for and use of a reasonable estimate of anaerobic energy expenditure to better quantify total energy expenditure.
tl;dr Using heart rate as a proxy for calorie burns can result in significant errors.0
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