I like how neat things are when people think them all the way through. There's a thing called basal metabolic rate, which is the rate at which we burn calories when we're just lying around all day. A 35-year-old, 200-pound man who jogs for a half hour can look forward to burning through a cool 381 calories. But wait, to think the whole thing through, that same man has a basal metabolic rate of 1985.3. If that guy's BMR holds steady all day, then each hour he burns about 83 calories an hour just being alive. So then he actually netted 298 calories burned from that jog.