I'm bumping this topic again because I'm still miffed about this calorie differential between my old Polar and my new Suunto ;-)
I've now rung Suunto (in Finland...) and they won't disclose their algorithm (of course) and all they could suggest if my vitals are correct is to adjust my level of activity. So I changed it down to less activity (less efficient, more calories burned) and that didn't show any increase in calorie burn. And it was inaccurate to my real level anyway. I've put it back to 5-7hrs a week.
So I know that the only result of incorrect calorie burn is either too much or too little weight loss. But it frustrates me none the less ;-). I'm leaving it for now to see what happen over the month. I only weigh monthly anyway at the mo.
What got me going again on this frustration was my 26k three hour session at the weekend. My watch said I burned 1435calories for 180 minutes of running at an average HR of 146. That's less than 500 calories an hour but 146 HR is mid LSD, not a recovery run. I also climbed 875 feet. And just a side note I weigh 75kg (165lbs) and I'm 5'7" so though I may be efficient I am a lot of mass to move particularly uphill!
Does anyone have anything else to add to my frustration or am I just going to have to see what the scale says in 3 weeks? And apologies for my OCD. I just CAN'T let things go sometimes ;-)
Note: I just Googled this topic and it turns out on other boards there are much geekier athletes debating this exact topic. Suunto seems to return very low calorie burn for certain people (why not all people is the piece that might answer the question). And they don't disclose the math!
All the units use their own algorithms and formulas to do the estimation. Even formulas online, Sparkpeople, etc are an average over many people which may or may not apply to you. Other factors like what the weather is (hot or cold) while you are exercising, your exercise economy, etc contribute as well. If you find the new number is more accurate for you, then stick with that one.
Try not to get too hung up on the differences--any device outside a laboratory setting is just an estimate of the calories burn-they are great feedback, but these devices are designed more for training purposes than they are for telling you precisely how many calories you are burning. They use an algorithm (a mathematical equation) to determine calories expended based on the data you plugged in as well as feedback from your HRM. The problem is calories burn is not based on heart rate alone--calories burn is based on your body's ability to create heat using oxygen and expelling carbon dioxide--if you were to go into a lab to see how many calories you are burning for a particular activity, you would be hooked up to a mask that measure your oxygen intake and carbon dioxide output which is in direct correlation to your heart rate--but heart rate is not the only factor.
If you were to sit in a sauna your heart rate would jump due to the body's need to cool itself down, but this does not mean you are burning more calories. I tell my clients--while exercising is a great means to burning more calories than sitting on the sofa--I remind them that weight loss and fat loss are not an exact science--the functional activity (taking stairs, walking the dog, getting up during commercials, getting in 10,000 steps a day, etc) is far more beneficial to this goal than just one 60 minute run for weight loss.
I hope this helps! Congrats on the running!
Edited by: OFFWERUN at: 8/12/2013 (07:03)
Fitness Minutes: (1,032) Posts: 47 8/12/13 6:56 A
As a gross estimate, at about 130#, I have always figured around 100 calories a mile. By some charts this is pretty close, by some it is an overestimate. If you did close to 6 miles, I would guess 600 is more accurate. Just an estimate though.
I just used my new Suunto Ambit2 w HRM (GPS). I was using a Polar (non GPS) HRM for the last year. My calorie burn has always been pretty high compared to my partner but I wrote it off to my exertion being much higher than my partner. His HR is always lower than mine when we run together. So this weekend using my Suunto my normal regular 60min run at 151 average came in at 600calories. This would have normally been closer to 800 on my Polar. I even contacted Polar about why it was so high and all they said was check the vitals. They were correct (RHR, age, gender, weight, activity level, max heart rate).
So now the calorie burn is lower with the same vitals using Suunto. And 600cal for 60min is the rule of thumb isn't it?
Any ideas and opinions about who is more accurate based on 'methods'? Of course this now explains a small amount of the slow weight loss. 25% inaccuracy would be about 1000cal a week or 100g not lost...
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