Extra time: how smart exercise keeps you younger for longer | The Guardian

Creaking knees, stiff back, dodgy shoulders… Age is no friend to the human body. So how are veteran athletes like Roger Federer and Jo Pavey still at the top of their game? And what can you do to keep up? ... The buzz technique that has gained favour is high-intensity interval training (HIIT) in which bursts of intense activity – such as sprinting and cycling – are interspersed with periods of lower-intensity exercise...