Calories burned question

I have been using SparkPeople to track my food and exercise.  When I enter 30 min on the elliptical, it says that I have burned over 600 calories, but when I put in the treadmill at 4mph, it says a little over 300.  I don't think the elliptical is twice as much work as 4mph on the treadmill.  Any thoughts as to the accuracy of either number?

I use a simple calculation that may or may not be accurate but it makes sense to me. 70% of your body weight per mile.

the output on the elliptical machine will probably give you a whole other number.  and it depends on speed, resistence, did you use the arms?  I had a nutritionist tell me once that everyone burns "about" 100 calories per mile, regardless of whether you are running or walking.  REALLY?  Not only does that seem wrong, but decidedly UNFAIR.

I was told that it's 100 per mile for running only.

The thing is, faster people run more miles in the same time, so that's why it works out to be the same for most people.

So I guess anything burned is good!

Ok. So I think the elliptical is WAY off. 600 in 30 mins sounds on the high side. I'd google some online tools and see what they say as well. Lots depends on your height weight etc.

You're right tho - anything exercise is a good start.

J

If you really want to know what you burned, you need to invest in a good HRM, one with a chest strap. All the machines and online databases are just guessing.

 I agree with Mac....

For me I have to have a heart rate monitor with a strap.  Though I'm heavy and the machines estimate, they always over estimate because I'm heavy.  They don't take into account your heart rate, your exertiion levels, etc.  Machines and online calculators only take into account, age, weight and sex.

I love my Polar HRM, it tracks my HR and calories burned.  I just like to see the numbers....it's a motivator for me to work harder...

 I've been wanting to invest in a HRM, because I check my own while exercising but that gets old.  Are they expensive?  Does anyone have recommendations?

I got an okay one on closeout for $30. I think you can get a good one for $50-100 if you are a good shopper.

I eventually got a really expensive one that did everything because I got tired of having so many separate gadgets. Like my run computer, my HRM, and my bike computer. None of them talked to each other or uploaded online (well, except the Nike+) either.

But for just getting an idea, a cheaper one like a Polar F6 is fine.