HRM question

clarebrad

Hi All

I have recently (about 4-6 weeks ago) purchased a HRM Polar FT4. I love it but just have few questions about the cals burned. I do all the required things, wet it before use, wash every 5 wears etc. Most of the time the reading my heart rate seem right. however am curious on how it works . I find that some people burn way more than me and just wanted to knwo what is based on. When i do alot of these work outs, i know i am really working to my hardest and pushing my self. Highest HR reading is about 165 ish when am running or high cardio. I did a 60 min walk yesterday which had some hills, but hr wasn't that high, i was having more a rest day walk so didn't go hard out. Well i burned 447 cals, which is good, but not much less than times when i do a really big session. Is this right?