Fitness: Don't take old advice about sedentary behaviour lying down

Defining exercise used to be easy. Any activity that causes your heart to beat faster, your breath to accelerate and a bead or two of sweat to develop was exercise. Everything else wasn’t.
That’s beginning to change, as health experts start exploring a whole new body of research devoted to the spectrum of physical activity that lies between working up a sweat and sitting on the couch.
This low level of activity used to be classified as sedentary, which in large doses is detrimental t