Settings on Polar FT7 HRM

jersgirl060606

I am wondering if I have the settings accurate for my HRM. I work out doing Total Core Turbo Jam and then 20 Minute workout Turbo Jam for a total of 51 minutes working as hard as I can and my monitor only calculated 377 calories. I am 34 yrs old and have my MHR set at 183. It is a brand new monitor and it is calculating all the time so I have to assume it is accurate, it just seems really low.