After retiring from 35 years as a teacher, Jeff Kellert as a tutor and helped with monthly dinners at his synagogue. Later, he got certified to lead support groups every other week for the National Mental Health Alliance, an organization for relatives of people with mental illness. Altogether, Kellert, 71, volunteers about 30 hours a month.

The experience keeps him active, but just as important, he said, it has led to new friendships and he never expected in retirement. "That together with a good sense of self-esteem and self-confidence — I feel like I’m doing ,” said Kellert, of Albany, New York. “Retirement’s not what it used to be, sitting on your rocking chair knitting.

It’s so much more.” Volunteering also may help him live longer, providing what various studies have shown are a variety of Jacquelyn Stephens, a developmental-health psychologist at the nonprofit Mather Institute, in Evanston, Illinois, researches how to age well. She said volunteering would be good even if it didn’t have so many benefits.

“But it just so happens that it does, and especially for older adults,” she said. Eric S. Kim, a psychology professor at the University of British Columbia Vancouver, said his research has found a connection between volunteering and more positive emotions, and more social support.

“These things have downstream effects, such as increased healthy behaviors, as well as increased healthier biological function such as reduced inflammation,” said Kim. I.