Is a "full body" workout necessary for most people? Obviously you won't have much in the way of upper body strength, say, if all you do is bike commute. But my

Is a "full body" workout necessary for most people? Obviously you won't have much in the way of upper body strength, say, if all you do is bike commute. But my understanding is that the amount of exercise required to be healthy is much less than what most fitness enthusiasts are committed to. It wouldn't surprise me if simply biking to work were sufficient to net most of the vital benefits of exercise for most people. (And even if it weren't, I'd still doubt that a gym membership is necessary.)