It goes without saying that eating right and exercising are key to living a long, healthy life, but new research suggests social relationships can also influence concrete measures of physical well-being such as abdominal obesity and high blood pressure, all of which can lead to long-term health problems, including heart disease, stroke and cancer. The study builds on previous research that has demonstrated how loneliness can manifest itself in a physical way.

The Company You Keep

The study, published in the Proceedings of the National Academy of Sciences, found that people who have more social ties, or frequent social contact with family and friends, had better functioning and lower risks of physical disorders.

“Our findings suggest the early emergence and continuity of the physiological impacts of social relationships across the life course. They also suggest physiological vulnerabilities to social stress that may be specific to life course stages and relationship stressors,” researchers said in the study.

Researcher’s analyzed data from four nationally representative surveys of the U.S. population that covered the lifespan from adolescence to old age. They looked at three dimensions of social relationships: social integration, social support and social strain. They also examined how social relationships were associated with biomarkers of physical health — blood pressure, waist circumference, body mass index and circulating levels of C-reactive protein, a way to measure systemic inflammation.

They found that the amount of friends and social interactions one have was important for health in early and late adulthood. In the adolescent life stage, social isolation had the same effect on the body as physical inactivity, it raised the risk of inflammation by the same magnitude as physical activity while social integration protected against abdominal obesity. In old age, social isolation had a more detrimental effect on blood pressure than diabetes. These two life stages are when the development and maintenance of social relationships can be critical for reducing future health risks.

For middle-aged people, the number of social connections didn’t really matter. It was what these connections provided in terms of social support or strain that did.

"The relationship between health and the degree to which people are integrated in large social networks is strongest at the beginning and at the end of life, and not so important in middle adulthood, when the quality, not the quantity, of social relationships matters," Harris said.


The study found that the interplay between social relation deficits, behavioral factors and abnormalities in the body and its systems can, over time, lead to chronic conditions or diseases such as cancer. This reinforces the fact that social isolation or loneliness is not just a state of mind. The emotions associated with social isolation can eventually manifest as a physical illness.

A recent University of Chicago study found that loneliness results in the body producing fight-or-flight stress signaling which can interfere with the production of white blood cells — these cells protect our body against infectious disease a la Superman style. It also revealed that social solitude increase the risk of an early death by 45 percent.

Loneliness can affect a person in the same way as physical pain. A 2003 study revealed that the brain bases of social pain — which is usually caused by social isolation or exclusion — are similar to those of physical pain. This means when a person feels lonely, the brain respond in the same way as it would if a person felt physical pain. Previous studies have also linked loneliness to poor nutrition, disrupted sleep and increase dementia risk.

The recent study sheds some light on how social relationships impact health across the human life span, revealing that social support and strain, which is measured by the quality, not quantity, of a social connection, mattered more for middle-aged adults and continued to have health impacts in old age. In adolescence, however, social integration was more relevant to physical health than social support.

"Based on these findings, it should be as important to encourage adolescents and young adults to build broad social relationships and social skills for interacting with others as it is to eat healthy and be physically active," researcher Kathleen Mullan Harris said in a statement.

Source: Yang Y, Boen C, Gerken K, Li T, Schorpp K, Harris K. Social Relationships and Physiological Determinants Of Longevity Across The Human Life Span. PNAS. 2016.