Have noticed recently on my Garmin 405CX that the amount of calories it states I have used does not really correspond to what I think I should be burning. For instance, I have just ran 8 miles at a pace of 8.20 min mil, and bearing in mind I weigh 14 1/2 stone I would like to think I have burnt off somewhere in the region of 800+ calories but the Garmin is showing 297!! Is there some fault I am unaware of or some update that I have missed?
Cheers in advance