New heart rate monitor said I used 1388 calories during a workout...right. any advice?

I'm a little peeved because my new $100 timex heart rate monitor (with the strap) just said I burned over a thousand calories during my workout this morning. Right.

My current weight is 257, I worked out for 45 minutes on elliptical and 20 minutes of strength training. It says I stayed in "zone" (mine is set at 130-145) for approx. 35 minutes, some of the time was spent above zone, (in the high 140's).  
 
I'm such a numbers driven person, so I thought getting the watch would be more accurate than the HRM on the machines. But I just don't how this is possible, and the darn store won't take it back if I have a problem with it, I have to send it back to Timex.

Anyone else have experience with these things that can share advice? I'm dissapointed.

Thanks!!

So the good news - you're not going crazy. Based on the numbers you posted above the calories burned sounds totally off.

I'm going to assume you didn't turn it on as soon as you put it on but when you started working out right - this could skew the numbers if you wore it all day (or for several hours).

I'd check all your settings on the watch too (height, weight, age, gender etc) something might be off.

Good luck!

Just because the watch has a heart rate monitor doesn't mean it uses it to help calculate the calorie burn.

I know you said you have a Timex, but here is an example I am familiar with
The Garmin 305 forerunner does not.  But their 310 model does.
The 305 uses the standard approximation formulas.  Both of them will give you a calorie burned total, but the 310 is probably more accurate.
Right from their web site
305 Heart rate-based calorie computation: no
310 Heart rate-based calorie consumption: yes

You might want to check out their tech data for the Timex.

 Check your settings.  You may have to tweak your weight, age, etc.  Also try resetting your HR zones on your monitor.

I know mine (Polar) has been pretty accurate and as of late, it has become a little skewed.  So I'm going to have to reset it.

I am totally numbers driven, too.  And I know that for me, 1 hour of heavy spin, I can burn around 550 calories.  40 minutes of jogging on treadmill I burn around 300 calories.

On resistance training days, depends on how fast I move from one set to the next, if I am doing heavy weights, or body work/plyo.....the range is anywhere from 300-600 calories for an hour......

Here's a formula to use:

I use the HRM to get my average HR over the period in question and plug that into the formula. I ignore what the HRM says in terms of calories burned:

Using VO2max
Men: C/min = (-59.3954 + (-36.3781 + 0.271 x age + 0.394 x weight + 0.404 x VO2max + 0.634 x HR))/4.184

Women: C/min = (-59.3954 + (0.274 x age + 0.103 x weight + 0.380 x VO2max + 0.450 x HR)) / 4.184

If you don't know your VO2max, then put in 30. That's reasonable for an out-of-shape, overweight woman. It will go up as you get into shape though.

In addition to what Marie said, the weight is in kilograms if you are going to use that formula.

Scott

Oops. He's right about that!

I have a spreadsheet that does all that for me. I just put in my current weight, my average HR and duration of exercise.