Polar Watch and Burn Rate Question

aisha786

hello all,
I got a polar watch so I could see what my burn rate is versus depending on the machines and plus my personal burn while walking etc.

I just put it on for the first time ever and just wanted to wear it around and see what my caloric burn rate is for my normal day to day except for when doing exercises.

For 30 minutes of normal activity of whatever I normally do, some sitting, some taking care of my kids, household life...it says I burned 100 calories in 30 minutes. So was wondering so if I burn 100 per 30 mins that's like 2000 over 10 hours. I'm 200 pounds, 5 2, female, 39 years old. Does this sound wrong? It's different than the bmr calculators online which usually give me about 1500 or so at sedentary level (ie sitting, some movement etc).

The other question is, how will I know how much i actually burn in activity? Do I need to subtract my average per minute by minute burn rate eg 100/30 = about 3.3 calories per minute from the minutes I exercised?

Can someone please help me out. I'm really lost.

thanks all

aisha786

Sorry, wanted to add. I did an experiment and just sitting, just reading only, my watch showed 58 calories burned in 30 minutes. I am sure sleeping probably lowers this number so I can't correctly just multiply 58*2*24 to get my daily burn rate.


Can anyone sort out my mind? really, really super appreciated.

sijomial

What Polar watch? An activity tracker or a heart rate monitor?

If it's a HRM you are wasting your time I'm afraid. HRMs cannot and do not measure energy.
You simply cannot use heart rate as an indication of baseline calorie expenditure.

Imagine two identical people one with a resting pulse of 50 and one with a resting pulse of 75......

They can give a rough approximation of calorie expenditure for a suitable exercise, steady state cardio basically, but accuracy of that will depend if you happen to be average fitness with an average exercise pulse and that's it.

aisha786

My watch is Polar Ft4. So basically, I wasted my money? So how do exercise machines attempt to calculate calories when it uses the heart rate?

aisha786

Sorry, I have the watch and also the heart rate strap monitor that goes around the chest.

sijomial

It's OK for exercise but not as a wear all day activity tracker.
HRMs can be a useful training tool especially if you are doing endurance cardio. That's really what they are designed for - to count your heartbeats!

Calorie burn estimates for steady state cardio can be "reasonable" and usable but not necessarily accurate.
But if you use some common sense and consistency they are fine. I used an equally basic FT7 during my weight loss and now realise the numbers were inflated by about 10% to 15% - didn't stop me losing weight.

Simply go for consistency and make adjustments on your calorie balance over time based on actual results. Unless you are doing an exceptional amount of exercise any inaccuracies in your food logging are far more significant than inaccuracies in your exercise calories.

DeadsAndDoritos

Use it for your workouts. Keep track of your calorie intake, calories expended during exercise and changes in weight over a period of a few months in order to calculate your daily calorie expenditure. You can start out with MFPs estimate and see how it goes. I have logged my net calorie intake each day for the past 300 days (based on food intake minus exercise calories given by my Polar HRM) and used changes in weight to work out that my maintenance calories are between 1700 and 1800 (5'2", female, 145 lbs). So in order to lose 1 lb per week I need to net about 1200-1300 calories which turns out to be pretty close to MFP's estimate.

aisha786

thank you very much. One other thing is should I subtract my bmr from my calories burned as reported on my watch?

sijomial

aisha786 wrote: »

thank you very much. One other thing is should I subtract my bmr from my calories burned as reported on my watch?

Never seen a definitive answer on that one - only (sometimes conflicting) opinions.
I even asked Polar and didn't get an answer....

Purely anecdotally the calorie estimate from my more sophisticated and personally calibrated FT60 matches the estimate I get from a power meter almost exactly (that's power output derived so net calories not gross including RMR).

I never bothered subtracting my RMR but I also never strived for absolute accuracy when it's only an estimate anyway. Loads of factors can skew the figures so I prefer simplicity.

Sued0nim

I think net v gross calories confuses the majority and would stick with gross and sijomial's advice ..he's spot on

ScubaSteve1962

aisha786 wrote: »

My watch is Polar Ft4. So basically, I wasted my money? So how do exercise machines attempt to calculate calories when it uses the heart rate?

Only if you don't use it for it's intended purpose, (during cardio workout) which is what you're doing when using an exercise machine. The FT4 does not calculate in BMR you would need a Polar Activity monitor to do that.