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A four-week online training in loving-kindness meditation did not reduce physical pain or boost social well-being in healthy adults when compared with a muscle relaxation exercise, according to a randomized controlled trial published in PLOS One. Instead, participants who practiced progressive muscle relaxation reported an increase in perceived social support relative to the loving-kindness group, and neither practice outperformed the other on measures of pain. Even so, people whose sense of social support grew during the four-week study tended to endure a painful task longer at follow-up.
Loving-kindness meditation is a contemplative practice designed to cultivate warmth, kindness, and compassion toward oneself and other people. Unlike mindfulness meditation, which teaches practitioners to observe their breathing and present sensations with neutral awareness, loving-kindness meditation has an explicitly social focus. Practitioners sit or lie quietly with their eyes closed while mentally offering wishes for safety, health, happiness, and peace first to themselves and then to a widening circle of others.
Early clinical studies suggested that this practice might ease physical discomfort, with a 2005 pilot trial of patients with chronic lower back pain finding that an eight-week loving-kindness program reduced daily pain and distress compared with standard care. Separate biological research indicates that social bonding and pain relief share brain pathways, as warm social interactions trigger the release of endogenous opioids, natural pain-relieving neurochemicals such as endorphins that elevate pain thresholds.
Supporting this link, a 2016 study of healthy adults showed that people who held an uncomfortable wall-sit posture longer tended to have larger social networks. Building on these findings, Olivia Young and Katherine O’Connell of Georgetown University and their colleagues tested whether loving-kindness meditation could increase pain tolerance and lower subjective pain by strengthening social well-being.
“My hunch is that social connection might work a bit like a painkiller in the brain,” said O’Connell, the study’s corresponding author, who conducted the research as a doctoral student in the Laboratory on Social and Affective Neuroscience at Georgetown University and is now a social scientist at The Lab @ DC in the Government of the District of Columbia. “There are interesting links between social contact and pain in animals and some evidence in humans–though it’s mostly correlational. I was motivated to conduct this study because I wanted to explore the potential causal relationship between social well-being and reduced pain in healthy adults.”
The researchers conducted a two-arm randomized controlled trial between December 2020 and July 2021, during the early COVID-19 pandemic. The trial was registered on ClinicalTrials.gov and its hypotheses, design, and analyses were preregistered on the Open Science Framework, where the data and materials were posted publicly. The team enrolled 75 healthy United States adults aged 18 to 55 with no prior meditation training, chronic pain, mental health diagnoses, or regular pain medication use. Six participants dropped out, leaving 69 adults (average age 31, 64% women), meeting the 68-participant target for 90% statistical power to detect a small effect on pain tolerance.
Because pandemic restrictions prevented in-person visits, all testing took place remotely over video calls and online surveys. During a double-blind baseline session, conducted before group assignments were known, each volunteer performed a wall sit test to induce acute muscular pain. Participants held an unsupported seated posture against a wall with their eyes closed, saying “pain” when discomfort began (pain threshold in seconds) and “stop” when they could no longer endure it (pain tolerance in seconds). Afterward, they rated their pain intensity from 0 (“no pain”) to 100 (“worst pain imaginable”).
At baseline, participants also completed questionnaires measuring perceived social support (access to advice, companionship, and practical help), loneliness, and trait anxiety. For five days before and after the training, they completed nightly online diaries tracking daily helping behaviors, such as holding a door for someone, and time spent socializing in person or remotely. The researchers also tracked county-level COVID-19 case, death, and vaccination rates alongside daily ratings of physical and emotional isolation, mask use, and social distancing.
Participants were randomly assigned, with the randomization balanced by age and gender, to four weeks of loving-kindness meditation (34 participants) or progressive muscle relaxation (35 participants), completing six 15-minute online audio sessions per week (24 sessions total). The loving-kindness recordings, created and narrated by meditation teacher Sharon Salzberg, guided listeners to offer wishes for safety, happiness, health, and peace toward a new focus every three sessions, progressing from oneself to a benefactor, a neutral person, a friend, a distant friend, a difficult person, a group, and all beings. The muscle relaxation recordings matched the schedule and format, guiding listeners to sequentially relax muscle groups without social content. About five weeks after baseline, participants completed a follow-up video session repeating the wall sit and surveys.
Attendance was high in both groups, with participants completing about 88% of their sessions on average. Contrary to the researchers’ predictions, loving-kindness meditation did not outperform the control on any measure of social well-being. Instead, perceived social support rose slightly after muscle relaxation (from 28.4 to 29.2 on a 36-point scale) and dipped slightly after loving-kindness training (from 28.5 to 27.4), a difference between the groups that was statistically significant.
The unexpected advantage for progressive muscle relaxation, or PMR, over loving-kindness meditation, or LKM, stood out to the research team. “Our ‘control’ meditation, PMR, beat LKM on improving social support,” O’Connell told PsyPost. “And participants loved the PMR recordings, which are freely available.”
Loneliness fell after muscle relaxation but did not change after loving-kindness training, a difference between the groups that fell just short of statistical significance. Trait anxiety declined somewhat in both groups, more after muscle relaxation, but the difference between programs was not statistically significant. Changes in emotional isolation, daily helping, and time spent socializing were also not statistically significant.
Neither program outperformed the other on pain. Wall sit times rose by about 8 seconds on average after muscle relaxation and were essentially unchanged after loving-kindness training, but this difference between the groups was not statistically significant. Ratings of how much the wall sit hurt also did not change significantly over time.
At the start of the study, people who reported more social support tended to hold the wall sit longer, consistent with earlier research. In an exploratory analysis, participants whose social support grew over the four weeks also tended to show larger gains in wall sit time. The association was modest, and it was not statistically significant within either group on its own; in the muscle relaxation group, it was close to zero.
Asked about the size of the effects, O’Connell described them as modest: “Small, but I think they’re worth following up on.” As for the main takeaway for the average person, O’Connell said, “We found some evidence for a link between social well-being and pain; people whose sense of social support grew during the study also increased their pain tolerance, whichever meditation they did.”
These findings align with a separate 2026 randomized trial of healthy adults from the same Georgetown University laboratory and including four of the same authors, which examined loneliness and empathy rather than perceived social support and physical pain and similarly found that four weeks of loving-kindness meditation failed to outperform progressive muscle relaxation.
At the same time, the null results for loving-kindness meditation stand in tension with an 18-month meditation trial in older adults that reported increased feelings of connection. That earlier trial evaluated inner feelings of social connection following an intensive nine-month loving-kindness and compassion module in older adults, whereas the new study assessed perceived social support after a brief four-week online training in a general adult sample during the pandemic.
The authors suggest that the gap between their results and earlier positive findings may partly reflect weaknesses in earlier studies, many of which lacked an active comparison group and were vulnerable to expectancy effects. Consistent with that view, a 2018 systematic review and meta-analysis of randomized controlled trials found that meditation did not reliably increase feelings of social connectedness in healthy adults, and that compassion gains appeared only when studies used passive waiting-list controls or when the meditation teacher was a co-author. The researchers also propose that progressive muscle relaxation may have offered participants a respite or positive distraction from pandemic-related stress.
As with all research, there are some caveats to consider when interpreting these findings. Because the trial had no passive, no-treatment control group, it cannot establish whether the changes seen over time, mostly after muscle relaxation, reflected the training itself or other factors, such as practice with the tasks or improving conditions as vaccines rolled out in early 2021.
“We ran the study in 2020–21, when lots of people were stuck at home, so LKM may have sparked a desire for connection they couldn’t act on,” O’Connell noted. “We also had no ‘do nothing’ group, so it could be that both meditations actually helped to some extent compared to people not doing any meditation during this socially challenging time.”
The study also took place during a period of disrupted social routines among a sample of young, predominantly female, meditation-naive adults without chronic pain. To explain why benefits may not have persisted until the follow-up session, the authors point to an earlier study of a mindfulness program in which mood benefits lasted hours but did not carry over to the next day. Future research will need to test loving-kindness meditation under normal social conditions and compare it directly with other interventions designed to build social support.
Finally, administering the wall sit test over video conference was a practical innovation in which pain threshold and pain tolerance were strongly related at baseline, suggesting the remote test worked as intended, though remote pain testing still requires validation against laboratory methods such as thermal heat or cold-water immersion. Wall sit endurance also depends on leg strength and captures only one type of muscular discomfort.
Even with those constraints, O’Connell sees promising applications for remote pain testing in future studies to reach underrepresented populations. “Lots of next steps, but one to highlight is that we showed you can run a pain test over Zoom and replicate prior research,” she said. “I think it should help make pain research accessible to more people (e.g., in rural areas).”
The study, “Assessing the effect of Loving-Kindness Meditation on pain and social well-being using a randomized controlled trial design,” was authored by Olivia Young, Katherine O’Connell, Naomi Nero, Melinda C. Somers, Paige A. Freeburg, Mary Ann Dutton, and Abigail A. Marsh.