Our bodies age at different rates, sometimes closely correlated to the years we’ve spent alive, and sometimes less so. A new study links another factor to the speed at which our brains age: how much we help others.

Regularly volunteering can reduce the rate of cognitive aging by around 15–20 percent, according to research by a team from the University of Texas at Austin (UT Austin) and the University of Massachusetts Boston in the US.

The findings are based on approximately two decades of telephone survey data from 31,303 people aged over 50. Scores on cognitive brain tests were mapped against helping behavior – whether volunteering with an organization or simply giving friends, relatives, and neighbors a hand as needed.

“What stood out to me was that the cognitive benefits of helping others weren’t just short-term boosts but cumulative over time with sustained engagement, and these benefits were evident for both formal volunteering and informal helping,” says Sae Hwang Han, a social scientist at UT Austin.