The Cocktail Report (sounds really smart around your friends):
Researchers at Indiana University used epigenetic clocks (DunedinPACE and GrimAge2, which measure biological aging from DNA methylation patterns in saliva) to assess how "hasslers" affect the body's actual rate of aging.
A hassler is defined as someone in your close social network who regularly makes your life difficult, causes you problems, or stresses you out. Nearly 30% of adults in the study reported having at least one.
Each additional hassler was associated with approximately 1.5% faster biological aging per year and roughly 9 months of additional biological age compared to peers of the same chronological age.
The effect size is equivalent to about 13 to 17% of the biological aging impact of smoking, making hasslers a meaningful but previously unmeasured health risk factor.
Counterintuitively, family hasslers (parents, siblings, children) had the strongest aging effect, while spouse or partner hasslers showed no statistically significant association.
You probably already know who your hasslers are: the family member whose calls you dread, the coworker who manufactures conflict, the person who regularly makes your life more difficult for no apparent benefit to either of you.
A study published in PNAS by researchers at Indiana University has now put a biological number on what those relationships cost you.
Using DNA methylation (chemical modifications to DNA that serve as one of the most reliable measures of biological age), they analyzed social network data and epigenetic aging markers from 2,345 adults across Indiana.
The finding is direct: each additional hassler in your close social network is linked to approximately 1.5% faster biological aging per year and about nine months of additional biological age compared to people your chronological age who have fewer hasslers.
To put that in context, each hassler corresponds to roughly 13 to 17% of the biological aging difference observed between smokers and non-smokers. That is not a trivial number for something most people have simply accepted as a fact of social life.
Nearly 30% of adults in the study reported having at least one hassler in their close network, and about 10% reported two or more. The effects grew with each additional one.
The relationship-type finding is the most surprising part. Family hasslers showed the strongest association with accelerated aging, stronger than coworkers, neighbors, or other non-family connections.
Spouse or partner hasslers showed no statistically significant effect on either aging measure.
The researchers believe this reflects a structural reality: you can avoid a difficult coworker or end a friendship, but family ties carry obligation and embeddedness that make them harder to exit. The chronic, inescapable nature of those relationships appears to be what translates social stress into biological aging.
The association held up after controlling for smoking, adverse childhood experiences, prior illness, personality traits, occupation, and COVID-era conditions. The authors are explicit that the findings are correlational, not causal proof.
Still, the robustness across multiple sensitivity analyses makes this difficult to dismiss.
"These findings identify negative social ties as chronic stressors that shape aging trajectories," the authors write, "and underscore the need for interventions that reduce harmful social exposures to promote healthier aging.
Why Should You Care?
Most longevity conversations focus on what you eat, how much you exercise, and how well you sleep. This study adds a dimension that is harder to measure but apparently just as real: the people who chronically stress you out may be measurably shortening your healthspan.
The actionable takeaway is not necessarily to cut people off. It is to recognize that managing difficult relationships, setting boundaries, reducing contact where possible, or seeking support when you cannot, belongs in the same category as diet and exercise when it comes to protecting your biological age.
Sources:
1. Lee B, Ciciurkaite G, Peng S, Mitchell C, Perry BL. "Negative social ties as emerging risk factors for accelerated aging, inflammation, and multimorbidity." PNAS 122(8):e2515331123 (2026). https://www.pnas.org/doi/10.1073/pnas.2515331123
