Polar FT7 HRM overestimating my calorie burn?

laura_fat2fit · July 2012

Hi,

I bought a Polar FT7 HRM last week, I was really excited to use it and to get a more accurate calorie burn so I could manage my calories for food better.

Obviously, I know there is nothing ABSOLUTELY accurate, but I know HRM is the next best thing.

However, I think my FT7 is overestimating my calorie burn during my workouts at the gym and want to know if it is/isnt or if im doing something wrong.

When I got the FT7 out of the box, it asked for basic settings such as height, weight, age ect. All of these settings are correct, I have double and even triple checked to make sure that this is ok.

I am wetting the two strips on the strap of the HRM and placing the strap below my breasts(this is where I was told to put it).

I went to the gym, did 30min cross trainer, 20mins running and 10mins on the bike. Cross trainer and bike had high resistance, treadmill was on an incline. I was sweating and got a good workout. my HRM said i burnt 735cals for an hours work.

I put the same workout into MFP to see what cals it gave me, MFP said 607, which is 100cals LOWER than my HRM. I've been reading everywhere that MFP overestimates calorie burn so how can my HRM be even higher than that?

according to my HRM, i burnt 694 during a 60min spin class. 754 calories doing 120 minutes of "25min biking, 23min cross trainer, Resistance Training and 10min warmup/cool down walks." and 902 calories doing 120 minutes of "Resistance training, spinning class, 10min warmup and cooldown walks."

Do the figures above seem to high for what I was doing at the gym or am I just worrying too much?

I just don't want to be eating back my exercise calories if its way overestimated. Is there anything that I need to setup extra on my HRM?

Any input would be appreciated. Thanks

Laura

HannahsReturnToFitness · July 2012

To me they sound about right.

I purchased a heart rate monitor the other week too and have been using it when i've been doing my C25K. I went out last night and did the C25K plus an extra walk (because i ended up further away from the house than I expected!). In 55 minutes I burned 395 calories which was made up of C25K for 30 minutes and walking for 25 minutes. When I got back I felt that I had burned that many calories and my stomach felt empty!

I C25K again this morning and put slightly less effort in and the calorie burn was significantly lower.

I can imagine that if I attended an exercise class or did prolonged periods of exercise at the gym then my figures would be along the lines of yours.

bridies01 · July 2012

I think the HRM sounds about right. MFP overestimates for me on some things and underestimates on others. The problem is MFP can't judge your intensity.

For example, I have been running for a couple years now, so running at a pace of 9 or 10 min miles is pretty easy for me. MFP tends to overestimate my burn doing that.

But the other day I had the treadmill on a random hills setting and just walked at 4 mph. MFP underestimated my calorie burn on that one because I just put in walking at 4 mph and it didn't account for the fact that I was walking some steep inclines and therefore working harder.

I also can burn anywhere from 250 - 390 cals in a 45 min spin class - all depending on how hard I push myself and how hard I turn up the resistance - there is no way to capture that intensity in the MFP activity defaults.

katetaylor999 · July 2012

Sounds about right to me too. Look at what your FT7 shows your heart rate to be during your workout. Mine is always around 185bpm, going up to 200bpm sometimes and in an hour of that I can burn 800 calories or more! And yes, I'm dripping, red faced and panting at the end of it!

CHN_ · July 2012

Does your HRM come with a Fitness Test? It should be on the menu (mine is two clicks up, after the Data information). If it does, do this, as it's a setting that would help make your percentage and calories burned information more accurate.

I know the Fitness test is part of the FT70 and FT40, but I am not sure about the cheaper models.

I am asking because I have this on my own (FT40), and after I did a new Fitness test a few weeks ago, I was told I burned 50 calories less on 30DS than I had the day before, and my HR% was also lower. Because my older Fitness settings were from a year ago, when I was in worse shape.

kimmianne89 · July 2012

Yeah i'd say that sounds about right

MrDel · July 2012

Trust the HRM

firstnamekaren · July 2012

I say trust the HRM. Sometimes MFP calculates my burn higher than my Polar FT4, sometimes it's the opposite. It looks like you're working your butt off! Isn't it rewarding to see that high number?

laura_fat2fit · July 2012

Its been helpful to know that it seems accurate. I can calm down and stop worrying about overeating now

I will have a look when I am back home with regards to the Fitness Test on my HRM, I hadn't really looked at any other settings so maybe its on there.

Thanks for the replies everyone! x

karensoxfan · July 2012

I had the same questions as you when I first got my FT4. It told me I was burning more calories than MFP estimates and even more than the machine readouts, so I was skeptical, but I'm still losing weight eating most/all of my exercise calories. I still wonder how accurate it is, but since it's based on my actual continuous heartrate, I'm learning to trust it.

CHN_ · July 2012

I will have a look when I am back home with regards to the Fitness Test on my HRM, I hadn't really looked at any other settings so maybe its on there.

Check the manual as well, if it mentions anything about it there

LaurnWhit · July 2012

Bump

Marge321 · July 2012

Sounds right to me ! I own a FT7 polar watch and I can burn 600-700 calories for an hour long of cardio trampoline. We are used to think we don't burn that much calories because MFP and other sites tells us an average calories burned. But FT7 is set with your height, weight, age and most important, heart beat.

wellbert · July 2012

My FT7 also is higher than MFP. Go figure.

laura_fat2fit · July 2012

I say trust the HRM. Sometimes MFP calculates my burn higher than my Polar FT4, sometimes it's the opposite. It looks like you're working your butt off! Isn't it rewarding to see that high number?

It's totally rewarding! I find myself pushing harder to burn more calories now that I have it rather than just doing what I want to exercise. Its really motivating.

Only thing now is that I burn close to 800 and struggle with trying to eat back the calories because I'm not hungry. I go to the gym in the evenings after work so I don't really feel like eating after I get back.

findingfit23 · July 2012

Sounds about right to me

Melanie_RS · July 2012

it depends on how long you've been doing cardio. If you've been doing it for quite awhile, these numbers actually seem *really* high.

if you are new at cardio, they may be accurate.

geordiegirl27 · July 2012

Your HRM should give you accurate burn as been said its based on your details and your effort where MFP will be worked out as an average.

You could try doing some exercise at the gym & not put much effort in & you should see a difference.

DoOrDoNotThereIsNoTry1 · July 2012

I bought the same HRM last week and it seems accurate. It will calculate calories burned after your work oyt if you keep it on. Drones metabolism is different. Some of us have a higher heart rate based on health and fitness. MFP is generalized. Trust three HRM.