HRM help?

ameredith83

I purchased a HRM yesterday, but it is the watch type. I have recently started the C25K program. I used my HRM for the first time yesterday afternoon while doing C25K. My question is when should I actually push the button to start counting my calories? I pushed it as soon as I started my first 5 min brisk walk. The calories were adding up really slow, but once I started the running part, they started to add up quickly. By the time I had finished the 30 minutes, it said that I had burned 550 calories. My current weight is 164.6. Do you all think that this calculation is accurate? Thanks for any advice in advance. I really want to get this weight off, but I don't want any extra calories if this is wrong. Please help!!