From a brisk 15-minute walk, to getting regular sleep – doing these things from your 30s could help you stay fit well into your 70s.

By the time you reach your eighth decade of life, the chances are that you’ll probably be feeling weaker, stiffer, and perhaps a little less cognitively sharp than in your younger years. Your sleep patterns might have changed so that you feel drowsier in the evenings and then wake earlier. Most concerningly, going by population averages, it’s likely that you will be dealing with at least one chronic health condition.

Yet researchers, now more than ever, are convinced that this is not an inevitability. “Based on what we now know, most people could expect to live to 90 or even 95 in good health if they were to optimise their lifestyle,” says Eric Verdin, president and chief executive of the Buck Institute for Research on Ageing in California. “And that’s very far from where we are, where most people live to 65 or 70 in good health, and then become ill and suffer all the indignities of old age.”

While Verdin says that it’s never too late to improve your health at any age through making positive lifestyle adjustments, whether that’s exercising more, eating better or cutting back on alcohol, you will likely fare best if you start sooner. In particular, researchers have highlighted your 30s as a key decade when a number of physiological systems, whether that’s muscle mass and strength, bone density or metabolic regulation, begin to show the first subtle age-related changes.

“It does highlight this period as an important opportunity to reinforce behaviours that build long-term resilience,” says João Passos, a professor of physiology at the Mayo Clinic’s Kogod Center on Ageing, based in Minnesota.