In the first class of our course on making the most of your friendships, host Cristina Quinn learns what it means to be socially fit — and why it’s never too late to start getting those reps in. Cristina talks to Bob Waldinger, director of the Harvard Study of Adult Development — the longest longitudinal study on human happiness — about why friendships matter for our health and what we can do to assess our connections. He gives practical advice for how to take stock of, reinvest in or rethink our relationships, with exercises that can work as an ongoing social fitness regimen. You can learn more about the Harvard Study of Adult Development here. Waldinger and his colleague wrote a book, “The Good Life,” that includes more tips for finding satisfaction in human relationships. Subscribe to The Washington Post and connect your subscription in Apple Podcasts.