Are we really burning as much as we think at the gym?

I use the treadmill at the gym, and it calculates calories burned.  Of course, this is just based on weight, not on height or age or heart rate.  But still, it was a number to work with.

I'm putting this in the weight loss forum, because so many people add back their calories -- and thus incorrect information from the machines or calculators can throw a monkey wrench into the program.

My daughter has one of those heart rate monitors that you strap to your chest.  She got it to use for her running.  So I used it today.  I input my age, height, and weight, as well as my target heart rate zone.  And I wore it on the treadmill.  It makes it much easier to use the treadmill, because the treadmill picks up the heart rate information and I don't have to keep my hands on its own monitor.

I was on the treadmill for 60:01 minutes, 2.97 miles.  The treadmill said I burned 320 calories.  The heart rate monitor said I burned 286 calories.  I spent 47:18 minutes in my target heart rate zone (the goal was 40). 

286 compared to 320 . . . according to my calculations, that's a 12% difference. 

I am wearing the heart monitor for a couple hours today as I do my regular routine, to see what it says about how many calories I burn on average per hour at my "sedentary" lifestyle.  I'll report back. 

Oh God I hope so or I'm killing myself for nothing. LOL

Yeah, I'm always suspicious about that too. I have been thinking about investing in a HRM for just this reason (among others). It's a goal for my bday. :-)

Right now I use my ipod, but I don't trust it because it's been giving me weird readings for mileage. So then I pop the data into the calculator here, and get one number. Then I pop the data into my WeightWare program and get another number. It's frustrating!!

Ultimately, I've been going by the WeightWare numbers, because they are the most conservative of the bunch. For example today I walked briskly for 30 minutes and it said I burned 127 calories. I'm still suspicious that I burn more than it says, because there's no option for brisk-walking on hilly terrain (which is what I do), only on firm, flat surface.

At any rate, when I use my spreadsheet and calculate the entire deficit for the entire period I've been tracking (since mid-January), it nice and neatly calculates out to nearly exactly the amount of weight I have lost!!! So it's certainly close enough. The thing is, it hasn't been consistent: for example, one week I may have had enough of a deficit that I should've lost a whole pound, but I don't lose anything. But take it as a whole - for the entire time period, and the numbers work out.

if the numbers work out over time -- then I'd say you are hitting the nail on the head, jen.

that's one reason I'm wearing it several hours today, to see if my sedentary calories are what the calculators and my tanita scale says. 

As long as your losing, if that is your goal, and getting into shape that is what really matter in the end.  Right?

Just remember there are myriad other reasons to exercise, all related to physical or mental health besides just burning calories. 

It's nearly impossible to know *exactly* how many calories you burn, and even an HRM is not an exact science.  It's what I use, but it's still not the same as being hooked up to machines in a lab.  :) 

So keep up the exercise, even if it is a few calories less!

Ditto.  Lets just keep up the good work.

Yeah, I don't really trust the Tanita, other than the weight reading it gives me. It says my mainteance calories are something like 1850!! If that's the case, I should've lost far more weight by now!!

Also it says my BF% is 28-29%. I don't think it is... I think it's more like 21-22%, based on just eyeballing myself, and various calculators online that take measurements all over.

I have read the Tanita BF% are wildly inaccurate for 1) women and in particular 2) women who carry their weight mostly in their stomach and upper body. There's some explanation for why this is, but I can't remember ...  I could google it again if you're interested. Let me know!

P.s. The reason I want an HRM is because my resting heart rate seems to be abnormally low, but I *know* I'm still pretty grossly out of shape (getting better all the time though). So I don't trust the usual way to calculate it based on 220-age.

nothing in my post questioned the value of exercise.

nothing in my post suggested not exercising because we couldn't have an exact amount of calories expended.

my post simply warned that the exercise equipment at a gym might be estimating calories expended too high, and that information might be valuable to someone who adds back calories burned at the gym.

I don't add back calories, I use a range, based on sedentary-->light activity.  So it doesn't affect me.

But many others on this site do add back the calories.  If they are disappointed in their weight loss, overcalculating calories burned during exercise may be a reason.

It's always best to have some hard figures to compare, rather than just the general disclaimer that they are just estimates.

I cant wait to hear what it said after the day is done!  Let me know how close it gets to the cc calculation :)  

I've always questioned even CC's calorie burns.  There is just no way in 30 mins with light elliptical training that I burn 317 calories =_=;

I am sweaty and I try to keep my heart rate in the 130s, but really..

okay, some preliminary figures.

I already reported that the monitor said I burned 286 calories during my 60 minutes on the treadmill.

I wore the monitor for 9:48:40 this afternoon and evening, just doing stuff around the house that I usually do in my sedentary lifestyle.

My heart rate averaged 69 -- which is quite good, considering how heavy I am.  My heart rate just sitting on the couch watching tv dips down to 59. 

Maximum heart rate was 93--which confirms that I am sedentary.

I burned 985 calories during that time, which equates to 1.675 calories per minute.

Now if I am awake and up and around for 16 hours, that would make a total of 1608 calories for the daytime, at my usual sedentary rate.  My calorie budget is 1350-1550.

Of the 286 calories that registered during the hour on the treadmill, I would have burned 100.5 just being sedentary, so the exercise burned an additional 186 calories.  If I were adding back calories, I should add back 186, not 286. 

So my total daytime calories so far is 1794 calories.  And I still have to add in the calories burned during the 8 hours sleeping.  I am going to try to wear the monitor during the night tonite.

More tomorrow . . .

I did successfully wear the monitor during the night.  These are the stats:

time:  8:37:16

average heart rate:  54

maximum heart rate:  83 (I had to get up once with my gson)

total calories:  589

That makes it 1.139 calories per minute burned during nighttime sleeping hours.

8 hours sleep = 547 calories burned

16 hours daytime sedentary activities = 1608 calories burned

TOTAL = 2155 calories burned

My tanita scale last nite estimated my BMR to be 1594.  Multiply that x 1.2 to get sedentary = 1912.  x 1.375 for light activity = 2192

The calculator I use for BMR says my current bmr is 1442, multiply that x 1.2 to get sedentary = 1730.  x 1.375 for light activity = 1983.

So, the heart rate monitor is the highest, and is nearly equivalent to my Tanita bmr x light activity.

My current calorie budget is 1350-1550, and I usually fall in the 1400s.  Yesterday I consumed 1402 calories.  Take 2155 PLUS the extra 186 calories burned at the gym = 2341 calories - 1402 = 939 calorie deficit.  On non-gym days, deficits would range from 805-605 calories. 

I know this is much more technical than most people want, but I thought some might be interested to help determine if it's worth the investment to purchase one of these heart rate monitors.  I believe this Polar model sells for about $90.

I am going to redo the test next week, for a straight 24 hour period.  I'll report back if there is any significant difference.

Interesting!!

So if you've been averaging between 600-900 deficit, you must be losing at a rate of 1.4 to 2 lbs per week. Are you? If so, I'm envious. My weight loss average has been more like 0.4 lbs per week!!!

I'm particularly interested because if I recall correctly, and haven't got you confused with someone else, you and I are similar heights and ages, aren't we? Except you must have tons more muscle than me and be in better shape if your maintenance level is that high!!

For comparison, I'm 5' tall, 41 years old, and not really all that fit (ran a recent 5K in 33:54). Looking at my spreadsheet, and deleting all the days I did not track calories for whatever reason (vacation, business trip, or cheat days where I ate at maintenenance or above), it looks like this since Jan 21 when I bought my scale:

-  I have burned 10,261 calories by walking or running (i.e., purposeful exercise... other than that, I lead a *HIGHLY* sedentary life as a telecommuter)

- Eating back those calories on top of a 1200 base allowance, I have had a total deficit of 12,378... divide by 3500 gives weight loss of 3.53 lbs. Subtract from initial starting weight of 119, expected weight today is 115.4. This morning the scale read 114.4 and my moving average happens to be.... 115.4!

- What this means is that 1500 - plus whatever I  burn exercising that day - is my true maintenance level. Which is nowhere near your far more generous 2155!!

Sigh... I guess I either need to figure out a way to work in more activity in my daily living, or start weight training to increase my muscle mass, huh? That is, if I want to eat more... and I do.

Ooh Manewell I'm so very glad you've tested this out...not only is it informative to all of us, but it's a HUGE thing to know how your body really operates!  I've been toying with the idea of asking for a good heart rate monitor for my birthday in July.  I love health-related things :D

Definitely keep us posted when you try the 24 hr straight test-session!

jen, actually, my weight is coming off very slow these days.  I posted the reason why in the Body Composition thread.

Also, I've just recently increased the intensity on the treadmill.  I'm hoping that I start to see the scale dropping more aggressively as I keep this up.

But I did want to report another significant factor -- it appears to be very true, at least from preliminary tests, that exercise does increase your metabolism for a lot longer than the duration of the exercise.

I wondered if that was the case, so I put it back on a few hours ago.  For duration of 2 hours 39 minutes, doing my usual sedentary work, not having exercised today, I burned only 1.233 calories per minute.  This compares to the 1.675 per minute that I was burning yesterday.  1.675-1.233 is a difference of .442 calories per minute.  For the 9 hours 48 minutes, that's a difference of 260 calories. 

Add that to the 180 extra calories I burned, and you get a whopping 440 calorie (minimum) benefit from the one hour of exercise. 

That should be pretty good motivation to exercise daily, if possible. 

hey guys where can you buy one of these heart rate monitors thing?? and how much do they go for? as far as I can tell it seems like a good investment.. for those who have bought it, do you think it's worth the money you spent on it?

i am still trying to understand this!! i've come to the realization that i probably dont eat enough. manewell broke it down for me last week ......but still a little confused. For example: I burned 950 calories calories on the elliptical last night--so let's say that was generous and it really was only--900 and i burned 50 on the treadmill --so that's only 35 calories....then i lifted weights for 20 minutes -- 150 calories....not including ab work etc....my normal calorie expenditure @ sedentary is 2000, @ light 2300, @ moderate/very active 2600.......i've been eating more protein lately and have been feeling hungry more often. manewell please reply

I need a heart rate monitor too, where to buy (in the UK)?? Are the wrist strap ones (the ones like watches) as good as the chest strap ones? I always used to do 10% extra at the gym just incase the machines were lying to me, but now I walk to and from the gym i think that kind of evens it out. Still I would like to have an accurate reading.

I'm a huge number person so this is a great post for me to read. I don't really have anything to add except thanks for taking the time to post this.