Originally Posted by mac
Really? It takes me awhile to warm up, especially when I go running. After about 30 minutes I'm finally warmed up and loose and ready to go and... stop? Don't you start burning fat after 30 or 45 minutes of aerobic activity once all of your stored sugars are used up? It seems like you would never reach your "fat-burning zone" by stopping all the time to do your daily activities (work, school, etc.).
From what I've heard, 20-30 minutes of continuous aerobic exercise is considered "fat burning". The things is, those daily activities all burn calories (and/or stored sugars) too. Just the act of existing burns calories, so you don't necessarily have a large store of stored sugars to start with.