Doctor behind 80-year happiness study was ‘shocked’ by the biggest predictor of a long, healthy life

What if the secret to longevity wasn’t in the mind or the gut — but in the heart?

Speaking at the inaugural New York Times Well Festival on Wednesday, psychiatrist and researcher Dr. Robert Waldinger announced he and his team were “shocked” by “the biggest predictor of who was going to live long and stay healthy.”

Waldinger, the director of the Harvard Study of Adult Development — the longest-running scientific study of adult life — revealed it was “how connected you were to other people and particularly the warmth of your connection to other people.”

Apparently, the researchers were floored by these findings.

“How could our relationships actually get into our bodies and actually change our physiology?” Waldinger mused.

“The best hypothesis is that it has to do with stress, that in fact relationships — when they’re good — are stress relievers.”

After all, how we feel does manifest itself physically — you can feel your pulse begin to race and your breathing quicken when something upsetting or anxiety-inducing happens, and the opposite is true when you calm down, he explained.

Having someone to vent to, as it turns out, plays a pretty big role in that.

“People who don’t have connections with other people, those people don’t have the same stress regulation mechanisms in their lives that people with good relationships have,” Waldinger said.

The secret sauce is recognizing that it’s not enough to have relationships — you need to cultivate them as you would a garden.

Most of us don’t expect to be physically fit without putting some work into it — why would relationships be any different?

“The people who were best at relationships were the people who were actively involved in staying in touch with people, people who really nurtured their relationships,” he said. “Most of us take our relationships for granted.”

He went so far as to say people who are intentional about keeping in touch and fostering relationships had a “superpower” that “went under the radar.”

The best part is you don’t need to plan an elaborate trip or book a bonding activity to get the benefits. Little things, like actually making eye contact with the barista making your coffee or — heaven forbid — the TSA agent checking your passport, give us “little hits of well-being,” according to Waldinger.

It’s the latest appeal from an increasing number of experts reminding people that social connection is a fundamental part of being human — and an essential aspect of good health.

A recent study even identified socializing as one of the six factors you can control that lower the risk of dementia, stroke and depression — adding to existing research indicating it’s a boon for longevity.

It seems that’s easy to forget in today’s increasingly virtual world, as psychotherapist Kathryn Smerling previously told The Post she prescribes “socialization very often” to her clients.

Elsewhere in the NYT talk, Waldinger noted that our culture may not always steer us in the right direction when it comes to happiness.

“These badges of achievement that we all set out for ourselves — money, awards, followers on social media — those badges of achievement are quantifiable, so they look like they’re gonna make us happy, but they don’t,” he said.

“The culture can sell us this idea that if we just do all the right things, we’ll be happy all the time,” he added. “That is not true. Nobody is happy all the time.”

That said, next time you want to feel like a superhero — try calling your mom.