Join the gym, run up a mountain, sign up for spin classes. We are constantly being told to go to great lengths - and get very sweaty - to get fit. What if you just don't have the time or inclination? Jo Blodgett has the answer: activity "snacks" that you can almost effortlessly add in to your daily schedule. Blodgett is a senior research fellow at the Institute of Sport, Exercise and Health at University College London and has studied the impact that small bursts of action can have on your