Researchers Have Pinpointed The One Type of Strengthening Exercise That Makes People Live Longer—And It’s Not What You Think
The insight comes from the longest happiness study in history.
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If you’re looking to reboot your health this year, you might sign up for your first triathlon, kickstart a meditation habit, or cut down on ultra-processed foods. But the latest science suggests the best way to improve long-term health isn’t physical, it’s social: connection.
Strengthening relationship ties by exercising what experts call “social fitness” is the most influential brain and body hack. Like weight training staves off bone density loss as you age, social fitness counters the downstream effects of chronic stress.
“Not exercising your social fitness is hazardous to your health,” says Robert Waldinger, a psychiatrist and psychoanalyst at Massachusetts General Hospital and a professor of psychiatry at Harvard Medical School.
Waldinger directs the Harvard Study of Adult Development, the longest scientific study of happiness ever conducted. According to the psychiatrist, who recently summed up eighty-plus years of data in his book The Good Life (January 2023, Simon & Schuster), the formula for health and happiness hinges on positive relationships.
“If you regularly feel isolated and lonely, it can be as dangerous as smoking half a pack of cigarettes a day or being obese,” Waldinger cautions.
But even though humans are wired to connect, exercising social fitness can be tricky. There’s no clear roadmap for building—or maintaining—a solid social life.
“Like unused muscles, neglected relationships atrophy,” Waldinger says.
Luckily, Waldinger’s data points to actionable exercises we can all use to supercharge our social fitness.
Studying the Good Life
In 1938, amid the worst economic depression in American history, researchers rounded up 268 Harvard sophomores to better understand how early psychosocial and biological factors influence life outcomes. For over eighty years, a team—now led by Waldinger—has tracked the students and their families, following them through marriages, careers, births, diseases, and deaths. In the 1970s, 456 Boston inner-city residents who were part of another study focused on juvenile delinquency and resilience were incorporated into the Harvard study.
The researchers check in with participants every two years, posing thousands of questions on topics like mood and life satisfaction. Every five years, they take physiological measurements including brain scans and blood work. As of 2023, the ongoing study is still tracking all living members of the original participant set and over 500 members of their offspring. The trove of data provides an unparalleled window into what makes up a good life.
When Waldinger first joined the study as a young psychiatrist at Harvard, he had an inkling that conventional measures of success like achievement, status, and awards were mere distractions on the path to real happiness. As he delved deeper in the data, hundreds of subjects confirmed this suspicion. Across the study, neither wealth nor social class were correlated with happiness levels or longevity. Positive relationships, on the other hand, were consistently linked to happier, longer lives.
Other large-scale data reinforces this link between connection and longevity. One systematic research review from 2010, including over 300,000 participants, suggests people with strong social ties are 50 percent more likely to survive over a given period than those with weak ties. Loneliness and social isolation are associated with immune dysfunction and may even spike the risk of heart attack or stroke by an estimated 30 percent. To help prevent these negative health outcomes, it’s essential to foster social fitness.
What Is Social Fitness?
Scientists have been studying humans’ social psychology in formal labs and universities for over a century, but the idea of flexing your “social muscle,” like you would a bicep or quad, didn’t emerge until 2011. That’s when social neuroscientists John and Stephanie Cacioppo shared results from testing a 10-hour social fitness training program with the U.S. military. The team found that social fitness exercises such as doing someone a favor or practicing conflict resolution reduced loneliness and boosted well-being in soldiers.
While scientists and philosophers had linked positive relationships and optimal health for decades, the Cacioppos and their research team were among the first to suggest positive relationships could be analogous to physical fitness. And just like you can’t remain physically fit without exercising, social fitness—the ability to cultivate and maintain positive relationships— withers without consistent effort.
Social Fitness and the Loneliness Epidemic
When the first Harvard study subjects were in their 80s, Waldinger and his team asked them to look back on their lives and share what they were proudest of. Nearly everyone talked about relationships.
“Almost all said: I was a good parent or a good mentor. I had a good marriage or I was a good friend,” Waldinger recalls. “Almost nobody said: I made a lot of money, I won these awards, or I got to be the chief executive of my organization.”
The team went on to ask subjects: Who could you call in the middle of the night, if you were sick or scared? Some people rattled off a long list. Others couldn’t list anyone.
“That’s real loneliness—this sense that nobody in the world has my back,” Waldinger says. “The costs of that are huge. It makes us feel unloved and unsafe, and eventually breaks down our health.”
In 2023, at the most technologically connected moment in human history, people report feeling further apart than ever. Forty percent of older adults in the U.S. report chronic loneliness. Add in pandemic-related lockdowns and loneliness has hit record highs, culminating in what Vivek Murthy, physician, and former United States surgeon general classifies as a loneliness epidemic.
“When you lose emotional and social fitness, you lose everything,” says Emily Anhalt, a clinical psychologist, co-founder of Coa, a gym for mental health, and expert on emotional fitness who is not involved in the Harvard Study. “Everything in life is going to feel better if you feel connected to other people to get through the tough things and enjoy the good things.”
Like prescribing a dose of time outside, some physicians go as far to say that encouraging social interactions has the potential to have a healing effect on patients. Emerging data suggests cancer patients have higher chances of survival if they feel satisfied by their levels of social support. Some experts even liken social connection to a vital sign—that measuring people’s loneliness levels hints at general health as accurately as blood pressure or pulse.
A Social Cure
To combat widespread loneliness and reap the positive benefits of social connection, it may seem like we’re all supposed to be extroverts or party animals. That’s a common misconception.
Humans are social creatures, but we’re not all social butterflies. Loneliness is a subjective experience. It’s not about the quantity of friends or family you have, but how fulfilling those relationships feel. The antidote to loneliness for some may entail a vast social network, while a few close relationships work for others.
Anhalt says people should treat social fitness proactively. Rather than wait until they feel isolated, people should regularly nurture their social life, which elevates mental well-being by default.
“Our culture’s way of thinking about mental health is very reactive—we make people feel like they have to wait until things are falling apart to get support.” To Anhalt, that’s like waiting until you have early signs of heart disease to do cardio. “I want to help people think about working on their mental health more like going to the gym and less like going to the doctor.”
To exercise your social fitness, try this training plan outlined by Waldinger in his new book, The Good Life:
Map Your Social Universe
To kickstart social fitness, start with self-reflection. Like completing a basic strength training circuit to pinpoint weak muscle groups, the following mental exercises can reveal your shaky social muscles. First, in a journal or notes app, outline how you are devoting your time weekly, and to who. Then ask yourself: What am I giving and what am I receiving? Am I having enough fun with loved ones? Am I getting enough emotional support? Waldinger suggests taking this comprehensive social evaluation annually, maybe every new year or birthday.
Strengthen Keystones of Support
Rather than aim for a total social rehaul, focus on improving the valued relationships you already have. An easy way to do this is by asking loved ones: Is there anything I can do better in our relationship? Can I communicate differently, or should we spend more time together? Based on their answers, tailor your communication or quality time to benefit your inner circle.
A great way to level up—and maintain—healthy relationships is by scheduling regular contact, virtual or in-person. Pencil in a weekly coffee date with a mentor or plan a monthly Zoom call with high school friends. Remove some of the logistical barriers that make connecting feel like a chore. There’s no exact rep of weekly social interactions to hit. For some, one or two a week will suffice, while others may want to schedule daily opportunities for connection. Reflecting on how these interactions make you feel—energized or drained—can help you find your sweet spot.
Create New Connections
One exercise to keep your social muscles in good shape is by expanding your network. But making friends in adulthood isn’t as easy as it once was on the playground or soccer pitch. A surefire way to connect with someone new? Get involved in something you care about. If you love cross country skiing in winter, join a local club. If you enjoy getting your hands dirty outside, volunteer at a local community garden. These activities provide an immediate conversation starter with those who have similar interests. If you’re worried that no one would enjoy your company, volunteer your time to those who may be lonely like the elderly. Forging new connections at an older age may feel impossible— like running a marathon after years spent jogging 5Ks— but the effort leads to major benefits. Friendship shapes mental health and in turn, our physical well-being.
Do Emotional Push-Ups
And here’s a bonus tip from Anhalt: Do “emotional push-ups.” These include striking up conversations with strangers, saying thank you, or accepting compliments without deflection. Start small—Practice one or two emotional push-ups weekly. While there’s no shortcut to social fitness, regularly flexing your social muscles will add up to stronger relationships over time.