And science suggests these pangs for companionship aren’t just uncomfortable. Chronic loneliness can have significant effects on our physical and mental health. “What’s so powerful about loneliness is it affects everything — every aspect of health and well-being,” says Angelina Sutin, PhD, a professor of psychology at Florida State University in Tallahassee, who researches how personality and life events affect mental and physical outcomes. “This underscores the importance of social connection and being able to be part of a group.” It can bubble up as either an objective or subjective state. You could be objectively alone and crave companionship, or you could be in a crowded room and still feel alone in the world, says Julianne Holt-Lunstad, PhD, professor of psychology and neuroscience at Brigham Young University in Provo, Utah. For the past two decades, she’s been studying the protective effects of social relationships on health, and, in turn, the health risks associated with loneliness and isolation. While nearly everyone experiences loneliness at some point, it’s chronic loneliness that wreaks havoc on our health. Here’s a look at seven ways loneliness affects our health and well-being:

1. Loneliness May Lead to Poor Health Habits

Evidence suggests people who feel lonelier may engage in more unhealthy behaviors compared with people who feel more socially connected. These lifestyle factors play a key role in people’s health trajectories, Holt-Lunstad says. Her ongoing research on the COVID-19 pandemic is attempting to better understand how loneliness stemming from lockdowns and social distancing worsened our health overall.

“When people are isolated and lonely, they tend to eat more, they don’t work out, they get worse sleep. Their health-related behaviors become worse,” she says.

2. Loneliness May Interfere With Sleep

3. Loneliness May Increase Risk of Depression

4. Loneliness May Trigger Chronic Inflammation

5. Chronic Loneliness Increases Dementia Risk

Sutin says that people who were lonely had risk factors for diabetes, hypertension, depression, and other concerns, but even after adjusting for those shared risks, loneliness still predicted increased risk of dementia.

Making conversation and nurturing relationships with coworkers, loved ones, neighbors, and others is great for our cognitive health, Sutin says. “There’s something about connecting with other people, having a reason to get up in the morning to engage with the world that protects the brain. It’s about keeping the brain active and, on its toes,” she says.

6. Data Finds Loneliness Is Bad for Your Heart

7. Loneliness May Shorten Your Life

“When we’re alone or away from a group we, in essence, have to deal with everything by ourselves and our brains are much more vigilant. It’s like being in a constant heightened state of alert similar to a fight or flight mode,” Holt-Lunstad says.