Scientists are beginning to understand that ageing is not simply a linear process and we age, according to recent research, in three accelerated bursts: at about 40, 60 and 80 years old. In this episode from July, Ian Sample talks to Stanford University’s Prof Michael Snyder, who explains what the drivers of these bursts of ageing could be, and how they might be counteracted. Help support our independent journalism at theguardian.com/sciencepod