After decades of studying what makes people happy, Robert Waldinger, MD, has reached one penultimate conclusion: It’s the relationships, stupid. Now he’s on a mission to figure out why.

Waldinger, like many others, is turning his focus to understanding the biological mechanisms underlying his fundamental premise that relationships are good for your health and happiness. Unraveling the physiological bits and pieces that enable that conclusion will make it “more likely to believe that the finding is real,” as he puts it.

This is a continuation of a conversation with Waldinger on finding happiness in tumultuous times. (Read the first part of the conversation here.)  For the past 22 years, Waldinger, a professor of psychiatry at Harvard Medical School, has led the Harvard Study on Adult Development, one of the longest-running scientific investigations into human happiness and wellbeing. He is also a best-selling author and Zen teacher.

Your research points to relationship quality as a key factor in lifelong happiness. What’s next in the science of happiness that’s got you excited?

A great deal of research now is looking at the biological underpinnings of happiness, such as how much of happiness is predetermined by our genetics, by our inborn temperament. You probably know people who are cheerful almost no matter what’s going on around them, and you may know people who are gloomy even when things seem to be going great for them. We think that has to do with a kind of biological setpoint of mood.

Given that, how much of our happiness can be changed? How much of our baseline mood level can be altered through various activities? I’m very interested in these questions; we’ve studied them. More recently, we’ve been adding biological measures, and many other researchers are also looking at the biology of wellbeing and happiness.

What kinds of lifestyle changes might alter one’s inborn temperament or biological setpoint of mood?

All kinds of lifestyle changes. We know that various practices can change our state. One of the most powerful antidepressants–maybe the most powerful antidepressant on the planet–is exercise. Why is that? How does exercise change mood?

“One of the most powerful antidepressants–maybe the most powerful antidepressant on the planet–is exercise.”

Gratitude practice changes mood. Just remembering all the things that are not wrong and that are good in your life, instead of just focusing on the things that are not going well, changes mood. How does it do that exactly?

To find out, people are studying the mechanisms, just like we’ve been studying how social connection makes us happier and actually changes our physical health. We want to know how exactly that works, because if we understand the mechanism, we’re more likely to believe that the finding is real. We’re more likely to have confidence in the finding.

if you just see some strange correlation between A and B, you’re not sure. As we know, correlations can be misleading, they can be spurious, or they can be driven by some third thing that we’re not looking at. So one of the ways we find out whether a correlation between relationships and health, for example, is real is by trying to understand the mechanism by which that could occur.

What are you finding as to why relationships seem to be good for your health?

Much of the research now is focused on stress. We’re all subject to stress every day, but some situations make us more stressed–and more chronically stressed–while other situations allow us to recover from stress more easily, more quickly.

For example, loneliness and social isolation are stressors. That sets up chronic inflammation in the body. It weakens the immune system. A variety of things happen when we are more stressed. We’re meant to respond to stress with changes such as our heart rate increasing and more rapid breathing, but then we’re meant to go back to baseline when the stressor is gone. Our bodies are meant to calm down.

But some people, we think, don’t ever get back to baseline because they’re chronically stressed. They’re too isolated.

Relationships as stress management?

Relationships, we know, are stress regulators. They actually help us calm down in the face of stress.

“Relationships, we know, are stress regulators. They actually help us calm down in the face of stress.”

I mean, think about it. if I’m stressed because something happens today that’s really upsetting. I can go home and talk to my wife about it, and I can literally feel my body calm down. And it doesn’t have to be a partner. It could be a friend or [a close confidant].

But what if you don’t have anybody? Many people don’t have anybody. That’s how we think stress and stress reduction may relate to [relationships and] wellbeing.

In the same way, if I’m upset about something my wife is doing, but then I do a gratitude practice where I literally do the thought experiment: What would it be like if we had never met? What would my life be like if she weren’t here? And then I really start to feel differently, and I don’t care any more about how she loads the dishwasher. That kind of gratitude practice can [drive] a shift in attitude that can be stress-relieving.

Do you see the breakdown of relationships in contemporary culture as related to the surge in so-called deaths of despair?

It has a lot to do with that. We know that deaths of despair are much more common in areas where communities have broken down, where the factory closed years ago and so many jobs were lost and small businesses closed. These communities are a shell of their former selves, right? Those are often where there’s more drug addiction, more alcoholism, and more severe depression. Those are what lead to deaths of despair.

I would say the breakdown of community is a strong force in deaths of despair. We know that demographically and statistically. Other huge concerns are this polarization and increasing social isolation that we’re all facing now. People are terrified. They’re terrified of economic collapse; they’re terrified of climate collapse. In times like that, people get more isolated, they get more paranoid, they get more afraid of each other. That’s a bad situation for us as humans and for our health.

I do psychotherapy in my clinical work as a psychiatrist, and one of the things I’m seeing–and all of my colleagues are seeing–is the rise in agitation and anxiety that everybody’s feeling. It contributes to and it exacerbates the other hardships in our lives. Everybody has difficulties in their personal lives, but this cultural phenomenon of social division and paranoia and anger is adding to and fueling the suffering that people are experiencing already from the usual difficulties of living their lives.