Today's Flat Abs Tip

Get the most fat-burning power from your cardio.

You’ve probably heard of the “fat burning zone"—or seen it on the cardio equipment at the gym. But how the heck do you know when you’re actually in it?

You don’t need to grab the hand thingies on the elliptical machine every two seconds or wear a heart-rate monitor to find out if you’re in this magical zone. Instead, use the good old-fashioned use-anywhere “talk test," says Pete McCall, an exercise physiologist with the American Council on Exercise. If you’re working out hard enough to still chat but get out only a few words at a time—not have a full-on convo—you’re exercising at an intensity where, he says, your body is primarily using fat as its fuel source (as opposed to carbs). Easy enough, right?