The internet is awash with flashy fitness tips and contradictory recommendations. But after finding a 1950s military workout booklet favoured by Helen Mirren, our senior fitness writer Harry Bullmore says the best advice is that which stands the test of time “Live to be fit and be fit to live,” is as enduring a fitness mantra as you’re likely to find. You might be surprised to learn it was written more than 60 years ago. It is taken from the XBX plan – a 1950s workout booklet produced by the