‘There is a thrill to seeing your stomach getting flatter’: why I run

Since I started trudging up hills and around parks four years ago, I have become healthier, slimmer and sunnier – and sometimes I even enjoy itIt is a damp, grey morning in south London and I am outdoors, still half asleep. The wind cuts like a knife and all I am wearing is shorts, tights and a polyester jersey. My muscles have clenched from the cold and no amount of stretching or rubbing will loosen them. But I tighten my laces and start to run. Uphill, as if things weren’t bad enou