Hi.. A friend of mine told me that if you run at a sprint for a short amount of time (like a 10 minute sprint).. the body needs resources urgently, and will burn the muscle instead of the fat stores.. he says it is better to run at a moderate speed (jog) for a longer duration..as this will make the body uses the fat stores since it wont feel an urgent need to burn the muscle. Because of what he said, I changed my cardio routine to where I run longer (48 minutes as opposed to 20) and at a slower pace ( I peak at 5.0 miles/hr on my new routine, but would hit 6.0 miles/hr on my older one). Is this true? do you guys do sprints or jogs..? Which is better? Thanks!