A $2.55 Million Study Will Test Whether Daily Social Connection Slows Aging
A phone call made after a draining day, an invitation accepted despite fatigue, or an unexpectedly long conversation with a neighbor could influence more than a person’s mood. According to psychologist Susan Charles, these small moments of social connection may affect biological processes linked to cognitive decline, chronic disease and aging. Charles, associate dean of graduate programs in the University of California, Irvine’s School of Social Ecology, has received a $2,550,958 grant from the National Institute on Aging to investigate how daily fluctuations in social connection are related to long-term physical and cognitive health.
The project, titled “Linking Daily Dynamics of Social Connection to Physical and Cognitive Functioning,” will examine whether people’s day-to-day experiences of belonging, companionship and loneliness are associated with measurable changes in the body. Rather than treating social connection as a stable personality trait, the research will focus on its daily dynamics. A person may feel supported and socially engaged one day, then isolated or disconnected the next. Charles argues that these short-term changes could provide crucial information about how social experiences influence health over months and years.
Previous research has established a strong association between social relationships and better health outcomes, including lower mortality risk, improved psychological well-being and greater resilience during stress. However, many studies have relied on broad questionnaires asking participants how socially connected they generally feel. Such measures can conceal important variations in ordinary life. Charles’s team will investigate whether the consistency of social connection, as well as its average level, predicts biological and functional health. The approach could reveal whether repeated, moderate interactions produce benefits even when a person does not have an exceptionally large social network.
The researchers will draw on data from the Midlife in the United States study, widely known as MIDUS, one of the longest-running multidisciplinary investigations of adult health and development. The project includes two longitudinal daily-diary datasets covering nearly two decades. In one, participants completed nightly telephone interviews for seven consecutive days during waves conducted in 2002, 2014 and 2023. A second dataset contains two daily-diary waves beginning in 2012 and 2023. Together, the samples include more than 2,900 adults between 24 and 97 years old, allowing the investigators to compare patterns across adulthood and later life.
The MIDUS participants also completed extensive health and behavioral surveys, cognitive testing and physical assessments. Some traveled to a clinical research facility to provide blood and urine samples, complete physical fitness tasks and undergo biomarker analysis. This combination of daily reports and laboratory measurements gives scientists an unusual opportunity to connect subjective experiences with physiological processes. Instead of asking only whether socially active people are healthier, the study can examine whether a person’s own changes in social connection correspond to differences in stress biology, inflammation, cognitive performance or physical functioning.
One major target will be cortisol, a hormone released through the body’s stress-response system. Cortisol normally follows a daily rhythm, generally reaching its highest levels around waking and declining throughout the day. Persistent elevation or disrupted regulation can indicate chronic stress and has been associated with poorer metabolic, immune and cognitive outcomes. Charles’s team will also examine inflammatory markers, gene-expression profiles and measures of biological age acceleration. These biological-age measures estimate whether cells appear to be aging faster or slower than expected based on chronological age.
The investigators are particularly interested in “inflammaging,” the gradual rise in low-grade systemic inflammation that often accompanies aging. Unlike the short-lived inflammation that helps the body respond to injury or infection, chronic inflammation can damage tissues and disrupt normal regulation across multiple organ systems. It has been implicated in cardiovascular disease, diabetes, arthritis and some forms of dementia. The study will assess whether the level and stability of daily social connection are related to inflammatory biology, cortisol exposure and gene-expression patterns associated with inflammation and antiviral activity. The findings will not necessarily prove that social interaction directly causes biological changes, but they could identify pathways that help explain previously observed health associations.
Age will be a central part of the analysis. Social relationships matter throughout life, but the consequences of disconnection may become more severe as chronic illness, disability and reduced physical reserve increase. Older adults may also face shrinking social networks after retirement, bereavement, relocation or declining mobility. At the same time, meaningful social contact could provide emotional support, encourage movement outside the home and stimulate cognitive processes such as memory retrieval, attention and language. By comparing younger adults with people in their later decades, Charles hopes to determine whether social connection has different effects when the body is more vulnerable to stress and disease.
The research arrives as loneliness and social isolation are increasingly treated as public-health concerns rather than solely personal problems. The U.S. Surgeon General has described the issue as an epidemic, while the COVID-19 pandemic intensified separation from friends, relatives and community institutions. Charles’s goal is not simply to warn people about the dangers of isolation, but to identify when and how positive social experiences are most beneficial. If the study links regular social connection with healthier stress regulation, lower inflammation or stronger physical and cognitive functioning, it could support interventions that treat social contact as a practical health behavior alongside exercise, sleep and nutrition. A brief conversation may not replace medical care, but repeated moments of connection could become an important part of preventive health strategies.
Subject of Research: Daily social connection, loneliness, aging, stress biology, inflammation, physical health and cognitive functioning.
Article Title: A $2.55 Million Study Will Test Whether Daily Social Connection Slows Aging
References: Susan Charles, University of California, Irvine; National Institute on Aging; Midlife in the United States (MIDUS) study.
Keywords: social connection, loneliness, social isolation, aging, cognitive decline, cortisol, inflammation, inflammaging, biological aging, gene expression, physical health, MIDUS, Susan Charles, National Institute on Aging
