hey, i've always wondered how much energy i burn when i'm at the gym... for cardio, the machines may give you a rough idea but even then i don't think they're very accurate... i figure i burn about 300 calories in a 20 minute cardio session... i use the cross trainer for 10 minutes and the bike for 10 minutes... the cross trainer asks for your weight and age before starting... how accurate would that be? it says i burn about 160 calories in a 10 minute session and the bike about 100... plus i usually bike/walk to and from the gym and always do a 5 minute warm-up run... i lift weights for about 45 min - 60 min fairly intensely... i don't lift to failure, but i'd say i lift a good amount for what i think my body can handle... so is there any way to get a rough idea of how many calories i'm burning at the gym? i'd really like to know how much i'm burning when i lift...