Physical health is influenced by social ties, although the nature of this link is not specified. According to a new study published in Social Psychology and Personality Science, impact of your close relationships may alter how your body operates.

Previous smaller-scale studies have examined the connection between relationship conflict or satisfaction with stress levels and blood pressure. The new research examines the effects of positive and negative relationship experiences on the body, as well as how these experiences and health outcomes change from day to day.

"Both positive and negative experiences in our relationships contribute to our daily stress, coping, and physiology, like blood pressure and heart rate reactivity," says lead author Brian Don of the University of Auckland. "Additionally, it's not just how we feel about our relationships overall that matters; the up's and downs are important too."

Over the course of three weeks, 4,005 participants completed daily check-ins via their smartphone or smart watch, providing assessments of their blood pressure, heart rate, stress, coping. Every three days, participants also shared reflections on their closest relationship, detailing their positive and negative experiences.

Researchers found that, on average, people with more positive experiences and fewer negative experiences reported lower stress, better coping, and lower systolic blood pressure reactivity leading to better physiological functioning in daily life. By contrast, variability - or daily ups and downs - in negative relationship experiences like conflict were especially predictive of outcomes like stress, coping, and overall systolic blood pressure.

Don notes that one broader implication of this study is that it is important to consider how outside stressors - such as the Covid-19 pandemic - can affect people's relationships, and therefore their physical health.

"Since the Covid-19 pandemic, relationships have been facing unprecedented challenges, turbulence, and change," says Don.

"What this means is that the Covid pandemic may have health implications not just because of the virus itself, but also indirectly as a result of the impact it has on people's relationships. That is, because the Covid-19 pandemic has created considerable strain, turbulence, and variability in people's relationships, it may indirectly alter stress, coping, and physiology in daily life, all of which have important implications for physical well-being."

Researchers cautioned against interpreting the study as proof that relationship experiences have physiological effects. Instead, the findings contain associations from daily life that illustrate how relationships and physical health are often intertwined. Causal conclusions, Don says, must be reserved for experimental studies.

In the future, Don suggests that researchers look beyond outcomes like blood pressure and heart rate reactivity to gain a fuller understanding of how relationships may affect health.

"It would be useful to examine other physiological states, such as neuroendocrine or sympathetic nervous system responses as outcomes of daily positive and negative relationship experiences, which may reveal different patterns of associations."