To lower your risk of heart disease and stroke, you need to get out and meet people. Loneliness and social isolation were linked to an increase in both conditions, according to a review of studies published online April 18, 2016, by the journal Heart.
Researchers examined 23 studies that involved 181,000 adults. Among this group, 4,628 heart-related events—such as heart attacks, angina attacks, or even death—and approximately 3,000 strokes were recorded. The data showed that loneliness, social isolation, or both were associated with a 29% increased risk of heart attack and 32% greater risk of stroke. The risk was similar to that of light smoking or obesity, according to the researchers.
Loneliness has already been linked to weaker immune systems and high blood pressure, according to lead researcher Dr. Nicole Valtorta of the University of York in the United Kingdom. While this was an observational study, she says the findings suggest that having a stronger social network is beneficial for your well-being and health, and that maintaining existing relationships and forging new friendships could be an effective form of disease prevention.
Efforts are underway to address the “epidemic of loneliness and isolation” affecting the country, as recently addressed by the U.S. Surgeon General Dr. Vivek Murthy who is laying out a “National Strategy to Advance Social Connection” initiative.
Virginia Tech neuroscientist Georgia Hodes says that reports of depression and anxiety are up at least 3-fold since the start of the COVID epidemic. “While loneliness and isolation are likely contributors, the COVID infection itself triggers a depressive episode in approximately 20 percent of people. Understanding how infection impacts mood may help us find new ways to treat individuals that do not fully respond to current antidepressants.”
According to the Center for Disease Control and Prevention, social isolation and loneliness have been linked to increased risk for heart disease and stroke, type 2 diabetes, depression and anxiety, suicidality and self-harm, dementia, and earlier death.
Hodes’ research explores biomarkers and treatments for depression that target the body’s immune response system. For studies linking loneliness and isolation to effects on the brain, she points to one study that showed “people who reported they were lonely but were otherwise healthy adults had greater pro-inflammatory immune responses to acute stress and immune activation. The data suggests that loneliness is priming the immune system to react more strongly to stress.”
Hodes says that most studies on loneliness in humans have been done in older adults. She points to a recent study by Isabelle F. van der Velpen et al, that used MRI images from the Rotterdam study to examine the relationship between loneliness and brain matter volume. “At baseline higher loneliness scores were associated with decreased white matter volume. Perceived social support correlated positively with total brain and grey matter volume. In general, though there is little on perceived loneliness and specific changes in brain structures in humans.”
“One of the most replicated findings is perceived loneliness in humans is related to higher levels of the cytokine IL-6 in the periphery. Previously, in mice we reported that altering IL-6 produced in the periphery by the white blood cells could induce or block the effects of stress on social behavior” says Hodes. “This is a protein that has increased levels when someone is sick. The human data suggest that loneliness is putting people into a constant state of low-grade inflammation which may then promote social withdrawal, depression and/or anxiety.”
In a study conducted in the lab as well as during the COVID-19 lockdowns, participants reported higher levels of tiredness after eight hours of social isolation. The results suggest that low energy may be a basic human response to a lack of social contact. The study conducted at the University of Vienna and published in Psychological Science also showed that this response was affected by social personality traits of the participants.
If we do not eat for an extended period, a series of biological processes ensue that create a craving sensation we recognize as hunger. As a social species, we also need other people to survive. Evidence shows that a lack of social contact induces a craving response in our brains comparable to hunger, which motivates us to reconnect. The related “social homeostasis” hypothesis suggests that there is a dedicated homeostatic system that autonomously regulates our need for social contact. However, we know very little about the psychological responses to social isolation. Moreover, we do not know how these findings translate to the social isolation we experience in our daily lives, including the unique context of the COVID-19 lockdowns.