Fit vs unfit: calories burned doing identical exercise?

mworld

If your VO2 max is 10 METs and you are working a 7 METs, you are working at a 70% effort. At 7 METs, an 80Kg person will burn ~ 560 Kcal/hr. If your VO2 max increases through training to 14 METs, that 7 MET effort is now 50% effort. Your heart rate will be noticeably lower. However, that 7 MET effort will STILL burn approx 560 Kcal/hour for an 80Kg person. It's just that now. the person can work at a 70% effort of 9.8 METs and burn ~780 Kcal/hour.

So to actually clarify this and make sure we read you right, you are saying that 2 80 Kg people doing the exact same activity will burn the same amount of calories in an hour regardless of their VO2 Max's being different and regardless of their bodies' composition (eg 1 of them is 40% body fat and has very little lean muscle mass and say the other one is 6% body fat with lots of lean muscle mass)?

More or less, yes. Any differences will be relatively insignificant given all other factors involved--e.g. the fact that anything we do related to calories--from estimating BMR to estimating activity calories, to estimating exercise calories, to estimating food intake calories, is all, well.....an estimate. So those differences you cite are going to fall within the general "error of estimate".

We tend to focus WAY too much on these trivial differences--that was the whole point of the blog. There are hundreds of comments a day on subjects like this that might amount to a difference of less than 5 percent, when most people could increase their workout intensity a tad, follow a more structured focused program, and with a combination of the improved quality of work and the improved fitness level that would come with it, increase their caloric burn by a substantially greater margin.

The main point I want to repeat over and over again is that using HRM data as "proof" of decreased caloric burn (in the absence of weight loss) is just 100%, no, 1000% wrong.

thanks for the explanation - always knew they were different, but knowing that the margin is igsignificant from a practical stand point is good.

DJH510

if only more people would read this thread! it might cut down the number of people obsessed with listening to their heart rate monitor to determine an "accurate" reading for calorie burn.

canstey

if only more people would read this thread! it might cut down the number of people obsessed with listening to their heart rate monitor to determine an "accurate" reading for calorie burn.

I agree. I listen to my HRM for calories burned and adjust my intake accordingly until my body says otherwise. If I am sluggish and/or weak during my routine or my body is screaming for food (not cravings) then I eat additional healthy calories regardless of what MFP and the HRM say and it has worked well so far. Now that I know that my HRM is reading a little low I can compensate for it a head of time.

mworld

Please don't let what azdak is telling you lead you to up your calories in any way!!! He's just always making the point that the HRM is a tool, and not accurate for a lot of things.

If you are using this site to figure out your before exercise calories and then adding in ALL the calories your HRM is telling you, then you are most likely already double dipping on some of the calories anyhow.

Example: HRM says 500 for your 1 hr, but you would have burned 100 calories doing nothing for that 1hr anyway and you chose a lifestyle that takes that 1hr of doing nothing already into account on your daily calorie needs.

So you were most likely already overestimating anyhow...so if the HRM is slightly low due to all the above, it may just get you closer to the reality if you are using the calories this site is giving you anyhow.

georgette70

bump

sweet4keeps22

bump

jb_sweet_99

Well my cousin and I do Kickboxing together and she burns 500+ and I burn 800+ Calories, she is about 4 inches shorter than me and about 60 pounds lighter. Hope this helps! :flowerforyou:

Amymhis

My thought is that you would burn less during a workout because you are straining less with the lower heart rate. However if you have more muscle in your body then your body is burning more calories throughout the entire day. So although you may burn less during your workouts, your body is burning more in combination with your metabolism to keep those muscles nourished.

Try HIIT training. (High Intensity Interval training) to get that heart rate booming and not beating yourself up throughout the whole workout!

LonelyPilgrim

I don't think you're ever going to find an exact answer. If everything was based solely on heartrate, then yes, the more fit person would burn less calories

but, like you said, the more fit person may have a greater muscle mass, so they continue to burn more calories for longer after the exercise than the less fit person, etc.

I know that if my husband and I ran together, it would certainly seem like I was burning a lot more calories.

Running an 8 min mile for 2 or 3 miles would be near max effort, where he can run sub 5:30 at his max effort.. so if he was running the 8min miles with me, he'd barely be working.. my HR prob 170s and his 120s or 130s.. but he's larger, and has a larger percent muscle mass than I do (he's 10-11% body fat at 5'10 and 152lbs where I'm 22% BF at 5'7" and 138ish) so his metabolism is probably higher, so maybe it equals out in the end? hmmm. not sure how you could ever get a definite answer on this.

countercycle

People think because they huff and puff they are burning lots of calories. All it actually means is their heart is beating fast.

A beating heart in isolation burns few calories, compared to calories burned by other larger muscles, such as muscles in legs.

If a fast heart beat could burn off calories, dieters would just join a sauna to lose weight.

Calories burned has less to do with heart rate, but more to do with simple physics, where energy used = mass x distance moved.

If you march an army from A to B, two persons of different fitness, weighting the same, and having the same body fat percentage, both carrying the same load burn roughly the same calories and so need to eat a similar calorific meal to sustain them.

Walking uphill at moderate speed burns 23% more calories and walking downhill burns 10% more calories.

As you get fitter your heart rate reduces per given Metabolic Equivalent Task (METs) and you can walk / run / cycle father before getting exhausted.

For someone unfit starting an walking or cycling exercise routine it more accurate to measure calories burned using a pedometer and watch, than an HRM, because the level of fitness changes makes an Heart Rate Monitor (HRM) for an unfit person rather subjective. The speed of the walk can be calculated from the distance over time, giving a METs value.

The calorific value of calories burned on an exercise can be calculated as: METs x Basal Metabolic Rate (BMR) x Time, less the amount a person would have burned anyway not doing the exercise, normally the Resting Metabolic Rate (RMR) x Time. And the BMR can be most accurately measured by the formula, BMR = 370 + ( 21.6 x Lean Body Mass}.

A HRM is very useful to show you how fit you get over time, if you compare reading for the same course over time. Its also invaluable for persons aiming to enhance fitness levels by working out in specific Heart Zones. It only becomes more accurate to use it for calories burned once you reach a constant level of fitness.

However for unfit persons wanting to estimate calories burned, use an inexpensive pedometer, bike computer or a more expensive GPS.

minizebu

Bumping to read later.

bcattoes

I would think differences in BMR would make a difference as well as differences in fitness. Two people of same height, sex, age, weight, and BF% are not going to necessarily burn calorlies at the same rate for any activity. There are so many other variables that could figure in.

rduhlir

Muscle cells build more mitochondria in response to the demands placed upon them by exercise. Cells themselves become more efficient. The type of muscle used during exercise will drive which cells develop.

Ultimately, if you can get your heart rate to the same point (same weight and age and other conditions the same), you should ideally burn the same amount of calories. But, as you train your body, and your cells become more efficient at waste exchange, it gets harder to raise your heart rate to that same max (for that same exercise).

Typically, as you get healthier and more conditioned, both resting heart rate and max heart rate for identical exertion will drop. That's why you can push harder longer-because identical workouts will require less and less perceived exertion as you get more fit.

Perfect explaination!

lilawolf

Bump for the incredibly interesting discussion. I didn't see much on a quick google search but a couple of the responses have been very informed and made a lot of sense.

juliemouse83

Bumping for a.m. Reading...

Azdak

I would think differences in BMR would make a difference as well as differences in fitness. Two people of same height, sex, age, weight, and BF% are not going to necessarily burn calorlies at the same rate for any activity. There are so many other variables that could figure in.

There are variables, but they are not enough to make a realistic difference. You will always have interpersonal variability--which is why research studies need a certain number of subjects and the variances have to fit within certain confidence levels in order to be considered significant. However, that variability is just in the normal human population.

For the most part, however, calories burned depends on intensity and mass--the nature of the mass is not that important.

Mr_Knight

Does someone who is more physically fit burn more, less, or the same amount of calories doing the identical exercise at the identical rate with weight of the two individuals being the same?

It depends on the exercise. The challenge is that the fit person can do many things the unfit person can't even complete, so on one level the fit person burns infinitely more calories than the unfit person because any number is infinitely more than 0.

And it depends on the unit you're quantifying by - for example, both will burn approximately the same number of calories running the same distance, but the fit person can burn far more calories per minute of running.

Interestingly, there is some evidence that the fit person burns more calories at rest (ie, "sedentary TDEE") than an unfit person, despite having a lower resting heart rate.

In a practical sense, the definition of "fit" is simply the ability to burn more calories in a shorter period of time.

Azdak

I don't think you're ever going to find an exact answer. If everything was based solely on heartrate, then yes, the more fit person would burn less calories

but, like you said, the more fit person may have a greater muscle mass, so they continue to burn more calories for longer after the exercise than the less fit person, etc.

I know that if my husband and I ran together, it would certainly seem like I was burning a lot more calories.

Running an 8 min mile for 2 or 3 miles would be near max effort, where he can run sub 5:30 at his max effort.. so if he was running the 8min miles with me, he'd barely be working.. my HR prob 170s and his 120s or 130s.. but he's larger, and has a larger percent muscle mass than I do (he's 10-11% body fat at 5'10 and 152lbs where I'm 22% BF at 5'7" and 138ish) so his metabolism is probably higher, so maybe it equals out in the end? hmmm. not sure how you could ever get a definite answer on this.

The answer is pretty definite. It's natural for people to speculate in discussion groups, but the actual science behind this question is simple and settled and it has been for decades.

If you are both running at a steady-state pace, then the oxygen cost of the activity is the same. Thus, the only difference in calories burned would be the difference in body weight. You are correct in saying it will "feel" easier for the more fit person to run at that speed, but that is because they have a higher maximum aerobic fitness level---but the fact that it feels easier does not mean the person is burning fewer calories.

Mr_Knight

Because of the wide spread use of HRMs, people have gotten the whole "calories burned during exercise" thing completely *kitten*-backwards.

This comes up, like, 800 times a day. Nice post, Azdak!

froeschli

Ok, I did not read all the posts, so forgive me if someone has mentioned this before:
But it's hard to find an "identical exercise" for any two people. Running, especially would not be it.
There is so much more to energy expenditure in running than simply body weight/muscle mass. For example, the other day, I saw a guy running: he sort of leapt forward into a deep lunge, pulled himself up and threw his other leg forward. He was sweating buckets and near to tears, but made very slow progress. An experienced runner runs very differently from that, minimizing loss of energy through proper technique and therefore using much fewer calories.
Cycling might be more standrdizable (forgive me, cyclists), since once you have clip pedals, the motion cannot vary as much as with running. Of course, you can still engage different muscle groups etc...