Intersting. The thing that comes to mind is that the group exercising for 30 min then resting then resuming exercise for an additional 30 minutes were able to push harder during the last 30 min then the group who worked out for 60 min straight. Did it mention what specific exercise they were doing? I must have missed that part if they did.
methinks gymgirl's got it there. Higher intensity means more fat burning. So the rest period allows more intensity during the 2nd 30 minutes than they would have if they just exercised straight through.
__________________ I will train with you. I will fight for you if you cant. I will die to save another. But I will bleed only for Kimberly.