2 options for cardio
#1 early AM empty stomach. This gives you the complete night to delepte glycogen stores by using them for the metabolic process.
#2 After resistence training
theory here is that resistnace exercise uses glycogen as it's primary energy source and cardio (when it an aerobic state) uses lipids(fat) for its primary energy source.
So if you do a warmup5-10 minutes light cardio to warm the blood up and get your head into the workout. then do your weight training you will have the fuel source to power thru the wrokout. Then you get on your cardio after. youve already depleted your glycogen stores so will be in a fat buring enviornment faster after the workout, get in your target Heart range and youre burning fat!!
If you do cardio first, you use up glycogen and dont buurn as much fat, then you try and do weights w/ no glycogen...defeats the purpose.
Bottom line. Do cardio first thing in the AM or after your resistance training.