It turns out that your relationships with friends can have just as big an impact on your health as your exercise routine. And if you're aiming for a long and happy life, you might want to pay attention to your social circle.
If you follow the news in the field of healthy living and longevity, you've probably noticed that researchers are paying more and more attention to our relationships.
We are told that people who have many friends and acquaintances tend to be much healthier than those who feel lonely.
Our social relationships are so strongly linked to longevity that the World Health Organization has just established a new Commission on Social Relations, calling its work a “global health priority.”.
You may be a little skeptical about these claims, as well as the mysterious mechanisms that may link our physical well-being to the quality of our relationships.
But in recent decades, we have begun to better understand the “biopsychosocial” model of health.
In researching these questions for my book The Laws of Connection, I found that our friendships can affect everything from the strength of our immune systems to our risk of dying from heart disease.
The conclusions of this study are clear: if we want to live a long and healthy life, our relationships with the people around us should be a priority.
The first studies on this began to appear in the early 1960s.
Then Lester Breslow of the California Department of Health and Human Services embarked on an ambitious project. He decided to investigate which habits and behaviors increase life expectancy.
To do this, he recruited nearly 7,000 participants from Alameda County, California. Using extensive questionnaires, he built an extremely detailed picture of their lifestyles, and then tracked their health over the following years.
Over the course of a decade, Breslow's team identified many of the ingredients we now know are essential for good health: not smoking, drinking alcohol in moderation, sleeping seven to eight hours a day, exercising, avoiding unhealthy foods, maintaining a moderate weight, and eating breakfast.
At the time, these findings were so startling that when the research team presented the results to Breslow, he thought it was some kind of joke.
However, research continued, and by 1979, two of Breslow's colleagues – Lisa Berkman and S. Leonard Syme – discovered another factor that influenced people's longevity – social connections.
On average, people with the most connections were about half as likely to die as people with fewer connections.
The result did not change even when the researchers controlled for factors such as people's socioeconomic status and health at the start of the survey, as well as smoking, exercise and diet.
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It became clear that all types of relationships matter, but some are more important than others. Good relationships with a partner and close friends had the biggest effect, but even casual acquaintances at church or the bowling alley also had an impact on lifespan.
It's understandable why these bold findings were initially met with skepticism by public health officials.
Scientists are accustomed to viewing our body as a kind of machine, largely separate from our mental state and social environment.
But since then, numerous studies have confirmed that relationships and loneliness have opposite effects on our susceptibility to many diseases.
Risk of serious illness
Social relationships can, for example, strengthen your immune system and protect you from infection.
In the 1990s, Sheldon Cohen from Carnegie Mellon University in the US asked 276 study participants about their social connections.
The participants in the experiment were tested for infections, then placed in quarantine and asked to inhale droplets of water containing rhinovirus, a virus that causes coughing and sneezing.
Over the next five days, many people began to develop cold symptoms. But they were less pronounced in those who had a wide and diverse circle of acquaintances.
People with the lowest levels of social connections had a three to four times greater risk of catching a cold than those who had active family connections, friends, colleagues, and acquaintances.
Any good scientist always considers other factors that could explain the result. It is logical to assume that lonely people may lead a less active lifestyle and exercise less.
However, as Berkman and Syme also found, this association persisted even after the researchers took these factors into account.
Furthermore, the magnitude of the effect far exceeded the benefits of ongoing vitamin supplementation – another measure we can take to strengthen our immune system.
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The impact of social life on our health even extends to the risk of serious chronic diseases such as type 2 diabetes.
A study of 4,000 participants in the English Longitudinal Study of Ageing found that a higher score on the University of California, Los Angeles Loneliness Scale – a questionnaire that scientists use to measure social connections – predicted the onset of type 2 diabetes within the next decade.
Scientists have even found some evidence that people with stronger social connections have a lower risk of developing Alzheimer's disease and other forms of dementia.
However, the most compelling evidence relates to cardiovascular disease.
Large studies that tracked the health of tens of thousands of people over many years have repeatedly highlighted this connection.
It is noticeable even in the early stages – people with poor social relationships are more likely to develop hypertension, and in the worst cases, loneliness increases the risk of heart attack, angina, or stroke by about 30%.
To assess the overall impact of social life on health, Julianne Holt-Lanstad, a psychologist at Brigham Young University in Provo, Utah, compiled the results of 148 studies.
Together, they covered 300,000 participants and studied the benefits of social integration and the dangers of social isolation.
The researcher compared the effects of loneliness with the risks of various lifestyle factors, such as smoking, alcohol consumption, exercise and physical activity, body mass index, air pollution, and taking medication to control blood pressure.
The results, published in 2010, were impressive.
Holt-Lanstad found that the quantity and quality of people's social relationships equal or surpass almost all other factors that influence human mortality.
The more people feel supported by others, the better their health and the less likely they are to die.
Overall, social connections – or the lack thereof – play a bigger role in people's health than alcohol consumption, exercise, body mass index and air pollution. Only smoking was close in impact.
