Ten minutes is not going to help much at all. You should really shoot for atleast 30 if your trying to loose bodyfat, and as stated above by jock191 (nice post) lower intensity equals higher percentage of fat being burned. Try to keep your heart rate at about 65% of your max. 220 - age divided by .65. For a twenty year old that's about 130 beats a minute. Not a very hard intensity to maintain for 30 plus mins.