“Over four decades of research has clearly demonstrated that social isolation and loneliness are both associated with adverse health outcomes,” Crystal Wiley Cené, MD, MPH, lead author of the scientific statement, said in a statement. “Given the prevalence of social disconnectedness across the U.S., the public health impact is quite significant,” Dr. Cené said. The very young and very old may be particularly vulnerable, the AHA notes in its scientific statement. Almost one-quarter of adults 65 and older are socially isolated and up to about half of them are lonely. Persistent loneliness may be even more common for Generation Z, young adults currently 18 to 22 years old. And the pandemic may have made things worse, for both of these groups, as well as for other socially vulnerable groups, including racial and ethnic minorities, individuals with disabilities, gender and sexual minority groups, and the poor. “There is an urgent need to develop, implement and evaluate programs and strategies to reduce the negative effects of social isolation and loneliness on cardiovascular and brain health, particularly for at-risk populations,” Cené said. Social isolation involves having little in-person contact with people you know well, like friends and family or members of your community. Loneliness happens when you have less connection with other people than you desire, or when you feel alone regardless of how many social connections you have. “Although social isolation and feeling lonely are related, they are not the same thing,” Cené said. “Individuals can lead a relatively isolated life and not feel lonely, and conversely, people with many social contacts may still experience loneliness.” To assess the connections between social isolation, loneliness, and heart and brain health, the AHA scientific statement examined research published through July 2021. Among the key findings of the research review:

Lack of social connection is tied to an increased risk of early death from all causes, especially for men.Isolation and loneliness are tied to increased inflammation and more physiological symptoms of chronic stress like fatigue, brain fog, headaches, sleep problems and weight gain.Social isolation and depression are a two-way street, each condition has the potential to cause the other.Childhood isolation is tied to an increased risk of several health issues in adulthood including obesity, high blood pressure, and type 2 diabetes.

One open question is whether social isolation or loneliness matter more for heart and brain health, because few studies have compared the relative impact of these two risk factors, according to the AHA. Another unanswered question is how different experiences of social connectedness over time might influence our brains and hearts. It’s not clear, for example, whether childhood isolation matters for people who have strong social ties as adults. Very little research explores interventions to address social isolation and loneliness as risk factors for cardiovascular health. What little research has been done to date suggests that exercise might be one way to combat these things in older adults, according to the scientific statement. The health consequences of loneliness and social isolation can extend far beyond just the heart and brain, according to the Centers for Disease Control and Prevention (CDC). Some previous research has found that these experiences can increase the risk of premature death from all causes by as much as smoking, obesity, and physical inactivity, the CDC notes. Social isolation and loneliness can increase the risk of dementia by 50 percent, make people more prone to depression, anxiety, and suicide, and raise the odds that they will require emergency medical care or hospitalization. Beyond this, people who are socially isolated or lonely can be more apt to have problem drinking, substance use issues, sleep disturbances, and limited physical activity, according to the National Institute on Aging at the National Institutes of Health (NIH). It’s not completely hopeless. The NIH offers these tips for coping with social isolation and loneliness — and minimizing the health risks:

Talk to your doctor. Be open and honest about how you’re feeling and your health habits, and be open to treatment for any medical issues.Set good lifestyle habits. Get regular exercise, eat well, and try to sleep 7 to 10 hours each night.Schedule activities and social interactions. Sign up for regular classes or volunteer shifts to have ongoing contact with people. Set appointments to stay in touch with family, friends, and neighbors every day, whether it’s in person or via text, email, or phone.