Training & Nutrition - Is my HRM broken or accurate?
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03-07-09, 03:27 PM
I just bought a polar F6 and have been using it when I ride. I am fairly new to training, but have been regularly riding for about 4 months.
Today I rode for an hour and ten minutes (including 5 minute warmup before, 5 minute cool down after). At the end of my ride it told me I burned 1375 calories in the 70 minutes with an average heart rate of 185. Is this way too much or is that possible? It just seems like a whole lot of calories for an hour ride. The area I ride is all flat with maybe 3 slight inclines (15 degrees max) each only about 100 feet so there was really no heavy climbing involved, however it was VERY windy today, and I was going against the wind for probably 70% of the ride. Average speed was 16 mph, and I did a total of about 20 miles.
Like I said, I am new to training, so just trying to see what is normal. If it helps, I am a 24 year old male, 6'1, 175 lbs.
03-07-09, 03:36 PM
Most HRM's report much higher calorie usage then actual, but yours seems really off the charts. I did a typical 1 hour ride today in mostly zone 4 and my Polar reported just over 700 calories. Your workout was probably harder, but not by that much, and we're close to the same size. On the other hand, you can eat another dinner tonight and not worry too much ;).
03-07-09, 03:39 PM
sometimes if you have clothing flapping heart rate montiors can pick up static from the flapping clothing and get an inaccurately high heart rate reading. Better contact (moisture) on the strap and less flappy clothes can fix that.
Maybe answering a few questions can help you assess the accuracy of the HR reading:
Did you feel like you were working that hard?
Is that average heart rate in line with other workouts you have done that felt similarly hard?
What's the highest heart rate you've seen while riding while you feel like you are working really hard?
That calorie number is a frequent point of discussion on these boards - you might try a little searching. You can google for some average calories burned figures for people of different weights doing different kinds of exercises.
My gut feel is you had an inaccurate high reading for part of your ride, probably due to flapping clothes in the wind, and since the Polar uses HR to calculate calories burned, that's also too high.
03-07-09, 04:50 PM
I have same issues in winter--one is dry skin and the monitor needs moist contact. the other is do no let your monitor or strap out in the cold--the cold soak pof the batteries will preclude the monitor from reading correctly (read your manual for specific temperature issues). Hope this helps!
03-07-09, 05:10 PM
FWIW I'm 26 6'0" and 250 and I did almost the exact same ride as you today. 24 miles, 15.5 MPH average (It was REALLY windy here) and my average HR was 144 and max was 177 based on my Garmin 305 which always seems consistent and accurate. I also have an F6 that I use at the gym and it's can give me some strange readings sometimes but it usually gets consistent after I start to sweat and create a good contact to my chest. Your HR numbers seem REALLY high to me so I would definitely question it. Maybe give Polar a call. My all-time max HR was 188 sustained for maybe a couple seconds during HIIT although I think mine is a little lower than "average" at least based on the 220-age formula which is pretty much useless.
03-07-09, 05:31 PM
Even when the Polar is getting accutate heart rate info, the calories burned that it reports is way too high. It's not measuring your output (unless you have the power meter option), it is just guessing.
03-07-09, 08:18 PM
Next time you're out measure your pulse manually for 15 secs and confirm whether the Polar is reading accurately.
Calories burned is a popular thing to report on various sports equipment. But if it is accurate, it is merely a coincidence. It is not possible for any of these things to measure calorie burn. They take something like heart rate and estimate calorie burn from it. But to do that with even a tiny bit of accuracy, you would have to put in: max heart rate, min heart rate, and weight. Even that would not be very accurate. The same rider being a bit out of shape and same weight could avg the same heart rate at say an 18 mph avg speed on a flat course that they would avg 21 mph after getting into shape. Calories burned is a fraud. So take it with more than a grain of salt.
03-08-09, 08:25 AM
Is this way too much or is that possible?Yes, those stats do seem high. However, if your are lean, and were working reasonably hard for an hour it definitely possible that you were approaching 1000 per hour cal expenditure.
I think its reasonable to assume you could average 185bpm for an hour, so if you want to adjust your HR to reflect cals more accurately you can input a different "setup weight" into the watch.
Perhaps setting the weight value to 150lbs will provide a more accurate value.
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