Lifetime of Friendships Slows Aging (Tyler Santora October 10, 2025, Nautilus)
For the new study, researchers compared social experiences across the lifespan of more than 2,100 middle-aged adults in the United States to the biological clock embedded in their DNA. The hands of these biological clocks consist of epigenetic changes to DNA—specifically, patterns in the addition of a chemical called a methyl group to certain genes. Such methylation doesn’t cause mutation; rather, the process turns the gene on or off in different cells of the body at different times. Over time, methylation patterns on certain genes change and can be used as markers of biological aging, a measure of how rapidly cells wear down that can be faster or slower than aging by the calendar. An older biological age is a strong predictor of chronic disease and early death.
The researchers measured social connection in a variety of settings over time to show that people with more social activity and sincere, long-lasting relationships aged more slowly. “We found that the depth and consistency of social connection, built across decades and different areas of life, matters profoundly,” says Anthony Ong, a psychologist at Cornell University. “Strong and sustained social networks appear to actually set back a person’s biological clock.”