, consider the pace you ran for your last 10-mile race or half-marathon. This pace is likely to be just below your lactate threshold, or roughly 80 to 85 per cent of your maximum heart rate, says Nick Anderson, the British cross-country coach. An even simpler
too could hold back the years. 20s Your running may still be improving, but your heart is already slowing down by around one beat per year. Your maximum heart rate controls the oxygen pumping round your body, as you age less oxygen is available
