Social Fitness: Train Your Relationships Like a Muscle

Social fitness is a simple idea with an uncomfortable implication. Relationships, like muscles, weaken when you stop using them, and most adults have been skipping the workout for years. The term comes from Robert Waldinger and Marc Schulz, the director and associate director of the Harvard Study of Adult Development, who used it to describe what more than 85 years of data kept showing: the people who aged best were the ones who kept actively tending their relationships, not the ones who happened to have good ones at 30.

This article explains what social fitness means, what the research suggests about why it matters, and why a weekly game night is one of the best training programs available. It is not a replacement for a therapist or a doctor. It is a way of thinking about friendship that makes it easier to keep.

What is social fitness, and where does the idea come from?

The Harvard Study of Adult Development began in 1938 with 724 participants: 268 Harvard sophomores and 456 young people from Boston’s poorest neighborhoods. It has since expanded to roughly 1,300 of their descendants and is one of the longest studies of adult life ever run.

Its headline finding, which Waldinger has repeated in talks and in the book The Good Life, is that satisfaction in close relationships in midlife best predicted who would be healthy and happy at 80, a better predictor than cholesterol or blood pressure at 50.

The second finding is the one that leads to social fitness. Relationships don’t maintain themselves. Waldinger puts it plainly: “Our social life is a living system, and it needs maintenance too.” Waldinger and Schulz use the term “social fitness” to make the point that connection is a practice, not a possession.

That framing changes what you do about it. You don’t wait to feel like calling a friend any more than you wait to feel like going to the gym.

Why does social fitness matter for physical health?

This is where the research gets striking, because the effects show up in the body, not just in mood.

Julianne Holt-Lunstad’s 2010 meta-analysis, which pooled 148 studies covering more than 300,000 people, found that those with stronger social ties had about a 50 percent greater likelihood of survival over the study periods, an effect the authors described as comparable to quitting smoking and exceeding physical inactivity or obesity. A 2015 analysis by the same group found that social isolation, loneliness, and living alone were each associated with higher mortality risk, on the order of 26 to 32 percent higher.

The U.S. Surgeon General’s 2023 advisory drew on this body of work to describe loneliness as a public health concern, associating poor social relationships with a 29 percent higher risk of heart disease and a 32 percent higher risk of stroke, and chronic loneliness or isolation with roughly 50 percent higher dementia risk in older adults, more than double the odds of depression, and premature death.

The proposed mechanisms are still being studied, but researchers point to chronic stress. Loneliness appears to keep the body in a low-grade state of alert, with effects on sleep, inflammation, and blood pressure. Regular, trusted company seems to turn that down. The research suggests the relationship is bidirectional, but the direction from isolation to worse health is well supported.

So social fitness is not a soft concept. By the numbers, it is in the same conversation as exercise and diet.

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Why is friendship so hard to maintain as an adult?

Because adult life removes every structure that made it automatic.

School put you in a room with the same people every day. Early jobs and apartments did a version of the same thing. By your mid-thirties, most of those structures are gone. People move, have kids, change jobs. Friendship goes from a default to a project, and most adults never pick up the project.

Rebecca G. Adams, a sociologist at the University of North Carolina at Greensboro, told The New York Times in 2012 that sociologists since the 1950s have seen three conditions as key to close friendship: proximity, repeated unplanned interaction, and a setting that encourages people to let their guard down. Adult life has almost none of those by default. If you want them, you have to build them.

Which is why the fitness metaphor is useful. Nobody expects to stay strong without a routine. Social fitness says the same about friendship: pick a routine, show up, repeat.

How does a weekly game night train social fitness?

Look at what a good training program needs and compare it to a standing game night.

The last row is the one most social advice misses. “Call a friend” is good advice that almost nobody follows, because an open-ended call has no structure. A game supplies the structure. You do not need something to talk about. You need to decide whether to take the blue tiles.

Games also give repeated interaction, plus the unplanned talk around it, which friendship researchers treat as the engine of the whole thing. Over six months of Thursdays, you learn how a person handles losing, what makes them laugh, when they’re tired, when something is wrong. That is intimacy built sideways, which is how most adult men in particular are willing to build it. The piece on how men make friends over board games goes further on that.

What does a social fitness routine look like in practice?

Keep it as plain as a workout plan.

1. One standing weekly commitment with the same people. This is the main lift. A game night, a run club, a dinner. Games have the lowest barrier and the most built-in structure.
2. A few small reps during the week. A text about the game. A link. A “you coming Thursday?” These are the warm-up sets. They keep the connection alive between sessions.
3. One stretch goal a month. Invite someone new. Have one real conversation past the surface. Reach out to someone you’ve drifted from.
4. Track it loosely. Waldinger suggests a simple inventory: who could you call in the middle of the night if you were sick or scared? Then ask when you last saw them. If the answer is “months,” that’s a muscle you’ve stopped training.
5. Expect it to feel effortful at first. Like any training, the first few weeks are the hardest. Social fitness compounds; the tenth Thursday is easy in a way the first is not.

If you don’t have a group yet, how to start a game night group walks through it step by step.

The LEV Institute, which the Ludarium works alongside, treats social fitness as one of the core longevity practices, alongside sleep, movement, and diet. The lounge is built to be the gym. The game is the reason. The people are the point.

FAQ

What does social fitness mean?

Social fitness is the practice of actively maintaining your relationships through regular effort, the way you maintain physical fitness through exercise. The term was popularized by Robert Waldinger and Marc Schulz of the Harvard Study of Adult Development.

What did the Harvard Study of Adult Development find?

Since 1938, the study has found that the quality of people’s close relationships at midlife predicted their health in old age better than their cholesterol or blood pressure did, and that close relationships mattered more to a good life than money or fame.

How often should I see friends for social fitness?

There is no established dose, but the research on habits and the Harvard study’s own findings favor regular, repeated contact. A weekly standing commitment with the same small group is a realistic and effective baseline.

Can board games really count as social fitness?

Yes. A weekly game night provides fixed people, a fixed time, repeated interaction, and a built-in activity, which covers the main conditions researchers associate with forming and keeping friendships.

Start training this week

The Ludarium is building a place in Indianapolis to do your social fitness the way you’d do any other kind: regularly, with people, and without having to host. New articles on play and health go to subscribers first. Subscribe to the Ludarium newsletter for new pieces on togethering for a lifetime.

Sources

• Work out daily? OK, but how socially fit are you?, Harvard Gazette: https://news.harvard.edu/gazette/story/2023/02/work-out-daily-ok-but-how-socially-fit-are-you
• Social Relationships and Mortality Risk: A Meta-analytic Review, PLOS Medicine: https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1000316
• Loneliness and Social Isolation as Risk Factors for Mortality, Perspectives on Psychological Science: https://www.psychologicalscience.org/journals/perspectives/1745691614568352/
• Our Epidemic of Loneliness and Isolation, U.S. Surgeon General: https://www.hhs.gov/sites/default/files/surgeon-general-social-connection-advisory.pdf
• Friends of a Certain Age, The New York Times (2012): https://www.nytimes.com/2012/07/15/fashion/the-challenge-of-making-friends-as-an-adult.html