Clocking up the miles

It’s often demonstrated that life expectancy, particularly over the past 30 years, has been ­increasing. It is often overlooked how much it can vary – in all sorts of different ways that seem almost designed to make life hard for those giving advice (although I’m sure that’s not the intention). In general, life expectancy has improved as a result of a large ­combination of factors such as purer water, cleaner air, better food, better housing, immunisation and even more leisure. But as you may expect, these ­factors don’t affect everyone equally. Just looking at two pieces of resear...