A randomized Barcelona-area trial found loneliness declined among adults using either organized group outings or independent nature activities, while those who entered the study lonelier and with poorer emotional well-being saw greater gains from recurring social contact.
By yourNEWS Media Newsroom.
Adults experiencing loneliness reported meaningful declines after spending more time in nature whether they participated independently or through an organized group, but those who began with the greatest loneliness and lowest emotional well-being benefited more from repeated group interaction, according to findings from a randomized controlled trial published Aug. 23, 2026.
The RECETAS-BCN trial followed 320 adults from 12 lower-income neighborhoods in the Barcelona metropolitan area, all of whom reported loneliness when they entered the study. Most were women, and the median participant age was approximately 63.
Across the full study population, researchers found no significant overall difference between the two approaches. Loneliness declined by about 10.5% after three months and approximately 16.8% after one year in both groups.
A different pattern emerged, however, when researchers examined participants according to their circumstances at the beginning of the trial. Adults who started with greater loneliness and lower emotional well-being improved significantly more through the organized group program than through independent nature activities. Participants who entered the trial with less loneliness and emotional distress had similar outcomes regardless of which approach they received.
The findings suggest that spending time outdoors may provide benefits on its own for some people, while individuals experiencing more severe isolation may gain additional support from the social relationships created through recurring group activities.
Participants were randomly placed into one of two approaches.
One group entered a nine-week program called “Friends in Nature.” Participants attended two-hour sessions once a week with a facilitator and other group members in outdoor settings that included parks, gardens and coastal areas. The meetings paired exposure to nature with conversation, shared activities and opportunities to repeatedly interact with the same people.
Participants assigned to the comparison group received a one-time motivational interview along with recommendations for nature activities they could pursue independently.
Researchers measured loneliness and health-related quality of life after three months, six months and 12 months.
Although loneliness decreased, the intervention did not produce a significant improvement in health-related quality of life in either group. The result indicates that reducing feelings of loneliness does not necessarily produce measurable improvements across broader dimensions of health and well-being.
The stronger results among the most lonely participants in the group program may point to the importance of its social structure. Unlike independent outings, the organized sessions provided regular opportunities to meet, talk and take part in activities with familiar people over nine consecutive weeks.
That distinction adds to research examining whether the benefits often associated with outdoor activity come primarily from nature itself, from human connection or from a combination of the two.
Studies of face-to-face interaction have suggested that in-person contact can provide benefits that solitary or remote activities do not fully reproduce. Other research examining responses to social agents has found that lonely individuals can evaluate social interactions more positively than people who are not lonely. Feelings involving separation, estrangement and loss have also been documented in therapeutic settings, particularly among people dealing with hospitalization or illness.
The Barcelona trial is part of growing interest in nature-based social prescribing, an approach that uses outdoor or community activities as a potential response to loneliness and related mental health concerns.
Community greening projects offer one example. By bringing residents together to create or maintain neighborhood green spaces, such programs can combine time outdoors with recurring social activity and opportunities to form new relationships.
At the same time, other research suggests that socializing is not necessarily the most effective approach for everyone.
A study published in the journal Health & Place found that intentional time alone in natural surroundings, including lakeshores, reduced loneliness more effectively than forced social interaction. Researchers identified a sense of connection with nature and attachment to a particular place as the strongest predictors of lower loneliness.
Taken together, the findings indicate that the circumstances of the individual may influence which approach is most useful. In the RECETAS-BCN trial, adults who were less lonely and had less emotional distress at enrollment did just as well when they pursued nature activities on their own. Those beginning with greater loneliness and poorer emotional well-being responded more strongly when nature exposure was combined with ongoing social contact.
The health implications of loneliness and social isolation have received increasing attention because separate studies have associated both conditions with substantial physical risks.
An analysis drawing on four long-running studies of aging included 80,050 adults in 31 countries. Socially isolated adults were found to be 26% more likely to become frail and 33% more likely to die during the study periods. Adults reporting loneliness had a 19% greater likelihood of frailty and a 25% higher mortality risk.
Separate research has associated high loneliness with a 19% greater overall risk of developing degenerative valvular heart disease.
Researchers have also examined the biological response to missing social contact. A Massachusetts Institute of Technology-led study found that cravings for human interaction can resemble hunger responses in the brain. After just one day of isolation, thoughts about social interaction activated the same brain region associated with food cravings during hunger.
Those findings help illustrate why interventions for loneliness may need to address more than simply whether a person spends time around other people.
The Barcelona researchers cautioned that their trial involved a relatively specific population. All 320 participants lived in lower-income neighborhoods in the metropolitan area, most were women and the median age was about 63. The results therefore may not extend to younger adults, men, residents of other economic groups or people living in different cultural and geographic settings.
The absence of significant gains in health-related quality of life also means the decline in loneliness observed during the trial should not be interpreted as evidence of broader health improvement.
Researchers said additional studies are needed in other populations and settings to determine whether the findings can be reproduced.
The results nevertheless add to evidence that loneliness is not necessarily best addressed with a single intervention. For some adults, independently walking, visiting natural areas or spending intentional time outdoors may be sufficient to reduce loneliness. For others, particularly those already experiencing greater isolation or poorer emotional well-being, the repeated social contact provided by an organized group may be an important part of the benefit.
Walking groups, community gardens, recurring outdoor classes and similar programs can combine access to natural settings with regular interaction among participants. The findings suggest that matching those options to a person’s existing level of loneliness and emotional well-being may be more useful than treating all forms of loneliness the same way.
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