Your significant other’s positive emotions can be contagious, especially in older couples. (Darren Baker/ Shutterstock)
In a nutshell
- Your partner’s happiness can lower your stress levels. Research shows that when your partner experiences positive emotions, your body produces less cortisol, the primary stress hormone. This effect is even stronger than when you experience positive emotions yourself.
- The benefits are greater in happy, long-term relationships. Older adults in satisfying relationships showed the strongest link between their partner’s happiness and reduced stress, suggesting that emotional support plays a critical role in healthy aging.
- Negative emotions don’t have the same impact. Unlike positive emotions, a partner’s negative emotions were not found to significantly affect cortisol levels, possibly because older couples develop strategies to shield each other from stress.
DAVIS, Calif. — When your spouse is in a good mood, you might feel happier too, but according to new research, their emotional state could be affecting you on a much deeper level. Scientists have discovered that when your partner experiences positive emotions, it might actually lower your cortisol levels, the primary stress hormone in your body, regardless of how you yourself are feeling. This biological connection between older couples adds a whole new dimension to what it means to be in a relationship.
“Having positive emotions with your relationship partner can act as a social resource,” says lead study author Tomiko Yoneda, an assistant professor of psychology at the University of California, Davis, in a statement.
The Aging Body and Stress Management
Study results, published in Psychoneuroendocrinology, are especially telling for older adults in committed relationships. As we get older, our bodies become worse at regulating stress responses, making us more vulnerable to the harmful effects of high cortisol. But a partner who maintains positive emotions might act as a biological buffer against stress.
The research team analyzed data from 321 older couples from Canada and Germany. These weren’t new relationships. The average couple had been together for 43.97 years. Each participant, aged between 56 and 87, completed surveys multiple times daily for a week, reporting their emotions while also providing saliva samples to measure cortisol. Partners completed surveys at the same time but separately, so they couldn’t influence each other’s responses.
Your Mood, My Body
When people reported feeling more positive than usual, their cortisol levels were lower. But when someone’s partner reported more positive emotions than usual, that person’s cortisol was also lower, regardless of how they themselves were feeling. In simple terms, your partner’s good mood might be doing your body good, even if you’re not sharing their happiness.
This connection extended beyond moment-to-moment measurements to total daily cortisol output. When someone’s partner reported higher positive emotions than usual throughout the day, that person showed lower overall cortisol for the day. This link was stronger for older participants and those who reported being happier in their relationships. In some cases, the effect of a partner’s emotions on cortisol was even stronger than the effect of one’s own emotions.
While a partner’s positive emotions were linked to lower cortisol, the researchers didn’t find any connection between a partner’s negative emotions and cortisol levels. Yoneda explained that this makes sense because older adults often develop ways to shield their partners from the physiological effects of negative emotions.
Quality Relationships Make a Difference
The emotional climate of your relationship may be an overlooked factor in your physical health. When your partner tends toward happiness, interest, or relaxation, their emotional state could be protecting your stress physiology.
This doesn’t mean you should pressure your partner to be constantly happy. Rather, these findings point to potential health benefits that come from fostering positive emotional experiences together. Creating opportunities for shared good times might be more than just relationship maintenance; it could be a mutual health boost.
“Relationships provide an ideal source of support, especially when those are high-quality relationships,” says Yoneda. “These dynamics may be particularly important in older adulthood.”
The association between a partner’s positive emotions and lower cortisol was most pronounced for people who reported higher relationship satisfaction. In happy relationships, partners may be more tuned in to each other’s emotional states.
Yoneda noted that these results fit with psychological theories suggesting positive emotions help us act more fluidly in the moment. These experiences can create positive feedback loops that enhance this capability over time. People in relationships can share these benefits when they experience positive emotions together.
Your partner’s happiness might be doing more than lighting up the room. It could be helping regulate your stress physiology in ways that boost your long-term health. In long-term relationships, emotions truly become a shared resource. What’s yours really is mine, right down to the hormonal level. So perhaps the age-old advice to “choose a happy partner” carries more biological wisdom than we ever realized?
Paper Summary
Methodology
This study combined data from three independent studies of older adult couples (321 couples total) from Canada and Germany who had been together for an average of 43.97 years. Participants completed electronic surveys several times daily for seven consecutive days, rating emotions like happiness, interest, relaxation, nervousness, anger, overwhelm, and sadness on a scale from 0-100. Simultaneously, they provided saliva samples that were later analyzed for cortisol. The researchers used multilevel statistical modeling to examine how one’s own emotions and one’s partner’s emotions affected cortisol levels, while controlling for factors like age, sex, education, health conditions, and medication use.
Results
The key findings showed that participants had lower cortisol when they personally reported more positive emotions, but also when their partners reported more positive emotions than usual – even after accounting for participants’ own emotional states. This “partner effect” was significant and, in some cases, stronger than the effect of one’s own positive emotions. The link was more pronounced among older participants and those reporting higher relationship satisfaction. Interestingly, while negative emotions were linked to higher personal cortisol, the researchers found no connection between a partner’s negative emotions and the participant’s cortisol levels, suggesting that older adults may shield their partners from the physiological effects of negative emotions.
Limitations
The study sample consisted primarily of healthy, retired older adults in long-term, satisfied relationships, limiting generalizability to more diverse populations. The participants were relatively homogeneous in terms of relationship structure (primarily mixed-sex couples) and cultural background. As an observational study, it cannot definitively determine the direction of causality between partner emotions and cortisol levels. The mechanisms underlying how a partner’s emotions influence physiological responses remain to be fully explained.
Discussion and Takeaways
The findings suggest that relationship partners’ positive emotions may serve as a protective factor for physiological stress responses. Since chronically elevated cortisol is associated with numerous health problems, having a partner who experiences and expresses positive emotions might contribute to better health outcomes over time. For older adults especially, whose bodies naturally become less efficient at regulating stress hormones, a positive partner may provide a valuable buffer against age-related changes in stress physiology. The research adds new dimensionality to the connection between relationship quality and physical health, suggesting that the emotional climate within relationships has biological consequences.
Funding and Disclosures
This research was supported by the Canadian Institutes of Health Research and the German Research Foundation, with additional support from the Canada Research Chairs Program. The authors declared no conflicts of interest related to the research.
Publication Information
The study, titled “‘What’s yours is mine’: Partners’ everyday emotional experiences and cortisol in older adult couples,” was published in Psychoneuroendocrinology (Volume 167, September 2024). The work was conducted by researchers from the University of California Davis, Simon Fraser University, University of British Columbia, Humboldt Universität Berlin, and Stanford University, with Tomiko Yoneda and Theresa Pauly as co-first authors.
