New study: Sharing joy is actually good for your health & heart

For many couples, sharing joy is almost instinctive — whether it’s a beautiful sunset, a child’s milestone, a small win at work, or an unexpected piece of good news. We naturally turn to the person we love to savor the moment and feel it more deeply together. A new study suggests that for older couples, these shared moments don’t just amplify happiness — they do much more.

The Calming Effects of Shared Moments

Tomiko Yoneda, assistant professor in the Department of Psychology at the University of California, Davis, and lead author of the study, explained that most research shows that positive emotions are good for health and longevity, but much of it treats emotions as if they happen in isolation. “In real life, though, our most powerful positive emotions often happen when we’re connecting with someone else,” she said.

Her team wanted to understand whether those shared moments actually show up in the body, not just in how we feel.

The study, published in the Journal of Personality and Social Psychology, analyzed data from three studies involving 321 older couples between the ages of 56 and 89. Over the course of a week, participants reported how they felt several times a day and provided saliva samples so researchers could track cortisol, a key stress hormone.

Participants rated how happy, relaxed, and interested they felt at each check-in. Moments were classified as shared positive experiences only when partners were together and both reported feeling more positive than usual at the same time. The results showed that couples experienced these shared emotional “uplifts” about 38 percent of the time — roughly one in three moments they were together.

During those shared positive moments, cortisol levels were lower. This link held even after accounting for each person’s individual mood, levels, like age, sex, and time of day, suggesting that shared positive experiences had a distinct calming effect beyond feeling happy on one’s own. The size of the effect is meaningful: cortisol was roughly half the cortisol increase older adults typically show in response to a standardized laboratory stress test. In other words, these moments had a real, measurable calming effect on the body.

However, not all positive emotions had the same calming effect. The study found that only shared happiness and shared relaxation drove the cortisol effect. They also found that when couples experienced positive emotions together, their stress hormone levels were lower at the next measurement. The calming effects didn’t end when the moment passed.

“When couples felt good together, their cortisol levels stayed lower later in the day. This suggests that co-experiencing positive emotions might actually help the body stay calmer over time,” Yoneda said.

The pattern was one-way. Shared positive emotions predicted lower cortisol later on, but lower cortisol did not make couples more likely to share positive emotions afterward — suggesting that the emotional experience drives the physiological change, not the other way around.

Even more interestingly, the study found that the calming effects held regardless of how satisfied people were with their relationship, meaning even couples who weren’t particularly blissful still benefited from shared positive moments.

How This Ties to Health and Well-being

Positive emotions don’t only feel good at the moment. According to the broaden-and-build theory of positive emotions, these emotions also temporarily open us up, almost like practice rounds that strengthen how we respond to life over time.

You may feel more flexible, more willing to try things, and more open to others. You’re also more likely to act in ways that gently expand your world — starting a conversation, going for a walk, trying something new, or reaching out socially. Basically, where stress narrows your responses into fight-or-flight mode, positive emotions widen the menu of what feels possible.

The findings also build on positivity resonance theory, which focuses on shared positive emotions rather than emotions experienced alone. In this framework, love is understood as a deeper connection between people that involves simultaneously shared positive emotions, along with coordinated behaviors and biological responses. These moments often include mirrored facial expressions, mutual responsiveness, and complementary physiological changes, reflecting a state of emotional and bodily alignment between people.

These shared experiences are thought to strengthen closeness and a sense of connection, reinforcing the emotional bond between partners. Research has also linked higher levels of positivity resonance to greater meaning in life and long-term well-being.

More broadly, decades of research show that happiness is associated with better health and longer life. An Asian study showed that happier older adults tend to live longer because they’re less depressed, mentally healthier, and more socially connected. In part, they also tend to have healthier lives.

At the same time, chronic stress plays a well-established role in the development and progression of many diseases, including heart disease, diabetes, and gastrointestinal disorders. Prolonged stress weakens immune defenses, fuels inflammation, and increases the likelihood of unhealthy behaviors such as poor diet, smoking, and substance use — further compounding health risks.

Share Your Happiness

Looking to de-stress? You may already be doing it without thinking — a shared laugh, a quiet moment of calm, or savoring good news together. These small, everyday moments matter more than we tend to realize.

Over time, they don’t just deepen connection; they may also help the body feel safer, calmer, and less weighed down by stress. All the more reason to tap your partner to point out a nice view or share a small win — because joy, when shared, has a way of settling both the heart and the body.