The health risks of prolonged loneliness are comparable to smoking 15 cigarettes a day, according to a 2023 report by former U.S. Surgeon General Dr. Vivek Murthy.

Research finds that strong friendships are commonly linked with reduced health risks and more biological markers signaling overall health. Despite the topic being underrepresented in the field, experts found that investing in efforts to build meaningful relationships can reduce loneliness and its subsequent health consequences.

People often underestimate the benefits of spending time with friends, said Hyewon Hong, a doctoral student in social psychology. He added that friendships play a critical role in supporting health and deserve the associated time investment.

Hong said his research at the Social Minds Lab and the Center for Friendship at UCLA focuses on the formation and importance of healthy friendships.

“You can imagine friends and your other relationships forming a protective bubble around you that shields you against … the negative effects of loneliness and stress,” Hong said. “Loneliness by itself has been shown to be really bad for you.”

Loneliness puts you at risk for heart disease, stroke, Type 2 diabetes, dementia and earlier death, according to the Centers for Disease Control and Prevention.

People who maintain strong social connections are about 50% more likely to live longer than those with weak or limited social relationships, according to researchers at Brigham Young University and University of North Carolina at Chapel Hill.

There is a misconception that loneliness is the opposite of having a full social schedule, said Eve Lefkowitz, the executive director of Conversations to Remember, a nonprofit that schedules weekly video calls between older adults and college students to increase social connections.

In reality, loneliness is characterized by the discrepancy between someone’s actual and desired level of social connection, according to the CDC.

Some people may socialize only 10% of the time and feel fulfilled by that, while others may socialize 95% of the time and still feel lonely and unfulfilled, Lefkowitz said. She added that one of the older adults in her program was seeking more connection despite having a very active social life with friends and family.

Hong said there is an indirect and direct pathway by which our relationships impact our physical health.

In the indirect pathway, social relationships influence physical health by buffering stress and loneliness, Hong said. Buffering stress and loneliness reduces dysregulation of stress hormones and inflammation that would otherwise contribute to disease and early mortality, Hong said.

He added that after hanging out with a close friend, you have more white blood cells, which protect against injury and illness, and less cortisol, which signals lower inflammation.

A study published in 2025 in the journal Brain, Behavior, & Immunity – Health found that sustained social connections are associated with slower biological aging and lower inflammation. Social relationships may include family relationships, religious involvement, emotional support and community engagement.

Alongside indirect effects, Hong said friendships also influence physical health directly by shaping health-related behaviors and norms.

Friends model healthy or unhealthy behaviors – such as exercising regularly, eating balanced meals or avoiding smoking – and reinforce social expectations that encourage individuals to adopt and maintain these behaviors.

If friends engage in negative health behaviors, such as heavy drinking or smoking, people are more likely to increase those behaviors themselves, Hong said. If friends engage in healthy behaviors like exercising, keeping a good sleep schedule and eating a balanced diet, people are more likely to adopt and maintain those behaviors as well, he added.

Yitzchak Ram, a third-year history student, said he and his friends help keep each other accountable for eating better, journaling to track habits and working out on a regular basis.

“My friend wanted to go to the gym, so we started going together,” Ram said.

Despite the importance of friendship in our lives, only about 17% of scientific research about close relationships is about friendships, Hong said.

“Romantic relationships are being hugely overrepresented,” Hong added. “A big reason why people don’t make time for their friends is they kind of underestimate how much benefit they’ll get out of seeing their friend.”

Intentionally building and maintaining friendships can counteract the cultural undervaluing of friendship.

According to the CDC, nurturing connections with people could include contacting loved ones, reaching out to a variety of people to build a broader support system or participating in communities centered on common interests.

Hong said joining groups that are related to your hobbies, especially if they are physically active hobbies, is a great way to foster relationships. Reaching out to old friends, engaging in new environments and remaining open to forming new relationships can also help, he said.

Reaching out to others for help is another way to address loneliness, Lefkowitz said. Some people never want to admit their loneliness because they feel that there’s a stigma, she added.

“I want people to understand that there’s nothing wrong with you just because you feel lonely,” Lefkowitz said.

Besides reaching out to others to let them know how you are feeling, one way to form friendships is through consistent exposure. A well-established principle in psychology known as the mere-exposure effect finds that repeated contact alone can increase feelings of familiarity and likability, according to the American Psychological Association.

In a study, strangers who simply appeared more often in a classroom – without interacting – were rated more favorably than those seen less frequently. These findings suggest that regularly showing up in shared spaces such as classes, clubs or hobby groups can naturally facilitate friendship formation over time.

Another way to decrease loneliness is to acknowledge that social relationships are a function of personal effort.

A study published by the Journal of Social and Personal Relationships found that people who believe friendship formation is within their control – viewing it as a function of personal effort – are more socially engaged. Higher levels of social participation, in turn, were associated with lower levels of loneliness.

Conversely, people who thought friendship was determined by external or uncontrollable factors experienced greater loneliness, according to this study.

Hong said researching the psychology of friendship has made him appreciate his friends more.

“If you have good friends, you will live longer, you will live happier and you will live healthier,” Hong said. “So go out there and make and keep good friends.”