BMF a lot lower than HRM?

graysmom2005

I JUST figured out how to check a certain time period for calories on my BMF (I'm technically slow. LOL!) The calorie count is WAAAAYYYY off from my HRM. I have had Polar HRMs and a Suunto HRM and they both gave me about the same. There is also a computer on my spin bike that reads Polars and it's pretty close too.

ANYWAY....the BMF has the calorie burn a LOT lower than my HRM. I mean by hundreds of calories in some circumstances. I know that HRM can be off by a bit, but for the most part Polars for example are thought of as really good monitors. Especially with the chest strap. Has anyone else found this? It will have me burning 400 calories for an hour of seriously hard core cardio when a HRM would have said 600+. Bodypump it clocks me in at under 300 when my HRM will say 400+.

So is my TDEE on my BMF even accurate? Is it low balling me or are my HRM crap?:grumble:

FaithHopeBELIEVE

Would like to know as well as I use an HRM.

Rae6503

I've read that the BMF is not accurate for bike riding since your arms don't really move. I've heard you can wear it on your calf to make it better, or I wear both sometimes and end up adding a couple of hundred to my BMF TDEE to make up for it.

For example: My BMF will tell me 700 or 800 for a 2 hour mountain bike ride but my HRM tells me 1200. If I add 200 to my TDEE that puts my burn half way between the two.

Noor13

I don't have a media device but I am thinking of getting one.

If it is the case though, that it does not accurately tell your burn for exercises I will go for the FitBit in combination with my HRM

PLUMSGRL

From other posts (from BMF users and the site) I gather that any exercise involving weighs will not be accurate.
Also, you're supposed to wear the BMF in your calf when spinning or biking for better accuracy.

UpEarly

My BodyMedia Fit is lower (dramatically) for all kinds of exercise - hiking, walking, HIIT (Tabata drills), biking, step aerobics, etc.

It also can't seem to distinguish the difference between climbing up a mountain carrying a 35lb. backpack from walking laps, with no pack, on a completely flat track. (I tested this!)

I talked to BodyMedia, and they told me that they are about to adjust their algorithm to calculate inclines/declines and biking more accurately. I keep waiting and waiting for them to release the update, but haven't seen anything yet.

I still really don't know what my TDEE actually is. BodyMedia says their device is 90% accurate, so I try to eat around 90% of my calories just to be safe. That's probably a little low though. I've been trying to maintain my weight, but I've continued to lose about a half pound a week since purchasing my BMF.

That said, I think the numbers on the BMF are probably more accurate (based on how my weight has changed) than what I was seeing on my Polar FT4 HRM. I don't use my HRM at all anymore.

graysmom2005

I've read that the BMF is not accurate for bike riding since your arms don't really move. I've heard you can wear it on your calf to make it better, or I wear both sometimes and end up adding a couple of hundred to my BMF TDEE to make up for it.

For example: My BMF will tell me 700 or 800 for a 2 hour mountain bike ride but my HRM tells me 1200. If I add 200 to my TDEE that puts my burn half way between the two.

Are you able to manually change your burn? How are you able to do that? Thanks!

graysmom2005

My BodyMedia Fit is lower (dramatically) for all kinds of exercise - hiking, walking, HIIT (Tabata drills), biking, step aerobics, etc.

It also can't seem to distinguish the difference between climbing up a mountain carrying a 35lb. backpack from walking laps, with no pack, on a completely flat track. (I tested this!)

I talked to BodyMedia, and they told me that they are about to adjust their algorithm to calculate inclines/declines and biking more accurately. I keep waiting and waiting for them to release the update, but haven't seen anything yet.

I still really don't know what my TDEE actually is. BodyMedia says their device is 90% accurate, so I try to eat around 90% of my calories just to be safe. That's probably a little low though. I've been trying to maintain my weight, but I've continued to lose about a half pound a week since purchasing my BMF.

That said, I think the numbers on the BMF are probably more accurate (based on how my weight has changed) than what I was seeing on my Polar FT4 HRM. I don't use my HRM at all anymore.

I hadn't been using my HRM either because I figured I didn't need to with the BMF. I then FINALLY learned how to take a time snapshot and was shocked at how low it was clocking me. I do put my strap on my leg for spin (If I remember) and it STILL was low. Hmmmmm

graysmom2005

With my BMF ON MY LEG yesterday, It said I burned 355 in an hour of teaching spin. Which is caca doodie. I burn between 600-700 in that 60 minute class. The spotlight on me makes me sweat like a mad woman, add in talking/singing (LOL) while I teach I burn a ton. 355 is way wrong. Holy heck...what is my real TDEE? Could it be EVEN HIGHER?:noway:

KarinFit4Life

If I were you Id phone bodymedia and ask them about the accuracy compared to ure heart rate monitor.
How long have u had it, its still new right?
I think I have heard that the accuracy level drops when a person is VERY active.... ? Would be good to confirm with them.

GoGoGadgetMum

I'm sure your spin calories would be closer to 6/700 in an hour. I'm not a teacher but go nuts and sweat like crazy on my spin and at 146lb 5ft2 I burn on average 10 cals a minute. This weekend 60 mins was exactly 600 cals and 32 mins 300 cals. Tis was on my polar. No way could I buy any other devices as I think my husband would have the men in white coats coming to get me

Noor13

No way could I buy any other devices as I think my husband would have the men in white coats coming to get me

*giggle*

amsparky

I'm having the exact same issue. I'm choosing to still go by my hrm for workouts, but what does this mean about the BMF? Can I assume it's an accurate indicator of my tdee?

Zylayna

I think the best thing to try to understand is how both the HRM's and the BMF measure up to a portable oxygen analyzer which (in the report below) is said to be the gold standard for measuring calories. I know that the BMF (as stated in report below) has a mean error <10%. What is the mean error of an HRM in regards to the portable oxygen analyzer- does anyone know? Both devices could be reading too high or two low and then when compared to each other the gap could be bigger without either being that far off. So, in all regards I'd say don't sweat it too much. If you use both, take an average of the two or just pick one and use it's numbers. Pick something to be your standard and go with that. You can always tweak as you get closer to goal and find out what works for you...remember it's all really an estimate game...but for now, just getting some stability in there will be what you need.

(Below is the report from BMF site)
BodyMedia FIT is Clinically Proven to be Accurate

The BodyMedia FIT System has been Clinically Proven to Accurately Measure the Amount of Physical Activity and Calories

A recent independent study tested our Armband system in real-life situations. Participants engaged in "free living" activities, including brisk walking, running, bicycling, sedentary activities, home activities, home repair, occupational activities, strength training, and ball games. The study compared the armband to a $40,000 "portable oxygen analyzer", the gold standard for measuring calories. Results showed:

Total Calories for free living activities: mean error <10%.
Total Minutes of exercise: mean error <5%.

Source: British Journal of Sports Medicine. July 2008.

(Also, I did read somewhere that the accuracy does drop for people with high burns (3000 or more...not for sure though)

Rae6503

I've read that the BMF is not accurate for bike riding since your arms don't really move. I've heard you can wear it on your calf to make it better, or I wear both sometimes and end up adding a couple of hundred to my BMF TDEE to make up for it.

For example: My BMF will tell me 700 or 800 for a 2 hour mountain bike ride but my HRM tells me 1200. If I add 200 to my TDEE that puts my burn half way between the two.

Are you able to manually change your burn? How are you able to do that? Thanks!

Oh, you can't really, not through their website. But since I use MFP to track calories consumed and the BMF to track TDEE, I track them both together in excel. I just add to my TDEE on my excel sheet.

LindsayE007

I am really curious about this too. I have had a BMF for about 2 months and just bought a HRM and have noticed the same big differences. So confusing!

ssdivot

It seems as though I see a lot of people saying that their BMF gives them a lower number for burn than their HRM's but for me it is the opposite. When I was doing Turbo Fire my BMF would say I burned 200 more than my HRM. I thought maybe because I was throwing my arms around crazily in turbo fire. If i go for a 4 mile hilly walk of 1:20 my HRM will say like 650 calories and the BMF over 800. I think maybe my HRM is off because there is a place to set V02 max and I have no idea if it is set right or not?

FaithHopeBELIEVE

No way could I buy any other devices as I think my husband would have the men in white coats coming to get me

*giggle*

I 2nd the giggle. My husband would do the same thing to me since I have an HRM and fitbit!

_Amy_Budd

I also have experienced my BMF recording a *higher* burn than my HRM - just yesterday I went for a run, and my HRM gave me a burn of 391, while my BMF recorded a 498-calorie burn. Go figure...

Truthfully, there have been times when I thought my HRM burn was unrealistically high, and others when I thought my BMF was on the low side... In the long run, I think it's best to pick one source and just go with it consistently. I like the BMF because it records my activity all day long, and when I look at my monthly numbers, I'm showing an average daily calorie deficit of just over 500 calories per day, which is even higher than the 300 I'm aiming for daily. So I'm going to stick with that, unless my measurements stop going down, in which case, I will reassess.


Amy

amsparky

Just thought I would report in - my HRM and BMF were within 10 cals of each other today. My workout was intervals, with a hilly walk afterwards.