It turns out that relationships with friends can have just as much of an impact on your health as playing sports. And if you want to live a long and happy life, you should 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 launched a new Commission on Social Relations, noting that its work is a “global health priority”.
You may be a little skeptical of these claims, as well as of 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 discovered that our friendships can affect everything from the strength of our immune system 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, the priority should be the relationships with the people around us.
The first studies of this began to appear in the early 1960s.
Then Lester Breslow of the California Department of Public Health began an ambitious project. He decided to investigate which habits and behaviors increase life expectancy.
To do this, he attracted almost 7,000 participants from Alameda County in 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 necessary for good health: not smoking, drinking alcohol in moderation, getting seven to eight hours of sleep a night, exercising, avoiding junk food, maintaining a moderate weight, not forget about breakfast.
At the time, these findings were so startling that when a team of researchers presented the results to Breslow, he thought it was some kind of joke.
However, the 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 a smaller circle of acquaintances.
The result did not change even when the researchers controlled for factors such as socioeconomic status and health at the start of the survey, as well as smoking, exercise and diet.
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Over time, it became clear that all types of relationships are important, but some of them are more important. Having a good relationship with a partner and close friends had the biggest effect, but even casual acquaintances at church or a bowling club also had an effect on life expectancy.
It is clear why these bold conclusions were initially met with skepticism by public health workers.
Scientists are used to seeing our body as a kind of machine, mostly separated 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 diseases
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 USA asked 276 study participants about their social connections.
Participants in the experiment were tested for infections, then quarantined 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 appeared to a lesser extent in those who had a wide and diverse circle of acquaintances.
People with the lowest level of social connections were three to four times more likely to catch a cold than those who had active family connections, friends, colleagues, and acquaintances.
Any good scientist always considers other factors that may explain the result. It is logical to assume that single people may lead a less active lifestyle and exercise less.
However, as Berkman and Syme also found, this relationship persisted even after the researchers took these factors into account.
In addition, the magnitude of the effect far outweighed the benefits of regular vitamin supplementation – another measure we can take to boost the immune system.
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The impact of social life on our health extends even to the risk of such serious chronic diseases as type 2 diabetes.
A study of 4,000 participants in the England Longitudinal Study of Aging found that a higher score on the UCLA Loneliness Scale - a questionnaire scientists use to measure social connections - predicted the onset of type 2 diabetes over the next decade.
Scientists have even found some evidence that people with stronger social ties have a lower risk of developing Alzheimer's disease and other forms of dementia.
However, the most compelling evidence concerns cardiovascular disease.
Large studies that tracked the health of tens of thousands of people over many years have repeatedly emphasized this connection.
It is visible 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 pectoris or stroke by about 30%.
To assess the general 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 blood pressure medication.
The results, published in 2010, were impressive.
Holt-Lanstad found that the quantity and quality of people's social relationships equaled or exceeded almost all other factors affecting human mortality.
The more people feel supported by others, the better their health and the less likely they are to die.
In general, social connections – or the lack of them – play a bigger role in people's health than alcohol consumption, exercise, body mass index and air pollution. Only the effects of smoking were close in impact.
