In new research published in Psychoneuroendocrinology, scientists have shown that loving-kindness meditation has a positive impact at the cellular level. The study examined how different types of meditation influenced telomere length, an indicator of physiological aging.

Telomeres are the end caps of DNA on our chromosomes, which help in DNA replication and get shorter over time.

“Chronological age and biological age are not identical. The former is measured in years, whereas the latter is often indexed by telomere length,” the authors of the new study explained. “Telomeres progressively shorten with cell division (i.e., aging) in general, but may also be replenished, or lengthened, by the enzyme telomerase.”

For their 12-week long study, the researchers recruited 176 participants between 35-64 years old from Durham and Orange County of North Carolina. All of the participants reported having little to no meditation experience.

The participants were randomly assigned to a 6-week loving-kindness meditation workshop, a 6-week mindfulness meditation workshop, or a waitlist control group. To measure telomere length, the researchers collected blood samples from the participants at the beginning and end of the study.

While the mindfulness meditation workshop helped the participants to cultivate a nonjudgmental attitude and focus on the present moment, the loving-kindness meditation workshop helped the participants to cultivate warm and friendly feelings towards others.

Overall, telomere length tended to shorten for everyone. “However, the daily practice of loving-kindness meditation appeared to buffer against that attrition,” the researchers said. Participants in the loving-kindness group “showed no significant telomere shortening over time.”

“Whereas participants in the mindfulness group, on average, showed significant telomere shortening over time, those changes were intermediate between the loving-kindness meditation and waitlist control groups,” the researchers added.

The study is not the first to find a relationship between meditation and telomere length.

Research published in the journal Cancer in 2014 found that telomeres maintained their length in breast cancer survivors who practiced mindfulness meditation. Additionally, a 2018 study in the journal Brain, Behavior, and Immunity found that telomere length actually increased in meditation retreat participants after three weeks.

But the new study was the first to compare loving-kindness meditation and mindfulness meditation.

The underlying mechanism that links meditation and the aging process is still unclear. The participants provided daily emotion reports throughout the study, but changes in positive and negative emotions had no relationship to changes in telomere length.

The study, “Loving-kindness meditation slows biological aging in novices: Evidence from a 12-week randomized controlled trial“, was authored by Khoa D. Le Nguyen, Jue Lin, Sara B. Algoe, Mary M. Brantley, Sumi L. Kim, Jeffrey Brantley, Sharon Salzberg, and Barbara L. Fredrickson.