HRM or MFP for running results?

SAC0O3

I know people always ask which is better, HRM w/ chest strap (I use bradenwm calculator) or MFP. MFP is usually always right on track with everything. When I run 30 minutes, it does pretty good estimating what my HRM said for 30 minutes. But when I run long runs (Hour long outdoor runs) MFP says I only burned 400 where my HRM says I burned 661 (591 if I subtract 10%) So which do I go by? I ran 64 minutes and my average HR was 153? What do you find works best for running?

DriedBrain

I have a heart rate monitor with a chest strap. I've also found around a 200-300 calorie difference between that and MFP. However on the tredmill it's only around 50cal difference when I enter my weight. I trust the heart rate monitor more because it takes in acount of hills, wind, terrian ect... It also continously monitors my heart rate, and based off the HR is how it judges how many calories you burn. Nothing is going to be completly accurate, but I think the HRM is more then MFP. Unless it's only a wrist watch HRM. Also take in consideration you burn 5cals for every 1 liter of oxygen you consume. The higher the HR, the more oxygen you consume. Somthing MFP can not judge. I love MFP though and they do a fantastic job for the information they have.