Loneliness speeds up aging, researchers find

By HPN Staff

Having a rich social life might do more than lift your mood — it could actually help slow down how your body ages.

A new study from researchers at Harvard and Cornell found that older adults with long-standing, supportive relationships showed signs of slower biological aging compared with their more isolated peers.

The study tracked more than 2,100 adults and found that participants with what researchers called a “higher cumulative social advantage” — meaning steady, meaningful connections with family and friends over decades — had lower levels of chronic inflammation and healthier cellular function. Both are key markers linked to longevity and reduced disease risk.

"What's striking is the cumulative effect — these social resources build on each other over time,” said Anthony Ong, lead author and psychology professor at Cornell University. “It’s not just about having friends today; it's about how your social connections have grown and deepened throughout your life. That accumulation shapes your health trajectory in measurable ways."

Why it matters

The findings add weight to growing evidence that loneliness can have serious physical health effects, especially among older adults.

Even as pandemic restrictions have faded, feelings of disconnection remain widespread. According to the University of Michigan’s National Poll on Healthy Aging, one in three adults ages 50 to 80 reported feeling lonely in the past year, and about as many said they still feel socially isolated.

The consequences can be severe. The AARP has called the loneliness epidemic a “public health crisis,” warning that chronic isolation raises the risk of heart disease, stroke, diabetes, dementia, and even early death. Researchers have estimated that the toll of loneliness on the body is roughly equivalent to smoking 15 cigarettes a day.

The costs are economic as well as personal. AARP estimates that social isolation adds about $6.7 billion annually in Medicare spending because of its impact on physical and mental health.

The big picture

Public health experts say the study underscores the need to treat social connection as a pillar of healthy aging — on par with diet, exercise, and sleep.

Jeremy Nobel, an instructor at Harvard’s Department of Health Policy and Management, said loneliness should be viewed as a fundamental biological signal. 

“Just like thirst is a biological signal that we need hydration,” he said. “Loneliness does impair our health, so it’s not surprising that we, our bodies and our minds, have generated a mechanism to tell us to go out and connect with others.”

Researchers recommend older adults take small, consistent steps to strengthen their networks — joining community activities, volunteering, or simply reaching out to old friends.