CU Boulder Study Reveals Nature Prescriptions Can Reduce Loneliness

One in three Americans and one in six people globally feel lonely on a regular basis, prompting public health concerns.

In Plain English: The Clinical Takeaway

• Social Prescribing: A system where healthcare providers connect patients with non-medical community services—such as nature groups—to improve overall health and wellbeing.
• Subjective Disconnect: The definition of loneliness, occurring when a person’s actual social relationships fall short of their expectations, distinct from simply being physically alone.
• Randomized Controlled Trial (RCT): A study design where participants are randomly assigned to either receive an intervention or act as a control.

Clinical Efficacy of the RECETAS Trial in Barcelona

The trial formed part of the broader RECETAS (Re-imagining Environments for Connection and Engagement) initiative, which launched in 2021 backed by a $5.6 million grant from the European Union. Jill Litt, professor of environmental health at the University of Colorado Boulder and principal investigator for the project, noted the previous lack of evidence for environmental prescriptions. The Barcelona site evaluated 320 lonely older adults across 12 low-income neighborhoods, as detailed in the Lancet Regional Health study.

Participants were split into two cohorts. One group engaged in structured, two-hour weekly sessions for nine weeks involving guided activities like nature-based art, birdwatching, or gardening alongside two trained facilitators. Both strategies worked. On average, participants registered an 11% drop in loneliness scores at the three-month mark, a 12% drop at six months, and a 17% reduction at one year.

Evaluation Timeline	Mean Reduction in Loneliness Scores
3 Months	11%
6 Months	12%
1 Year	17%

Impact of Chronic Isolation

Studies show that chronic loneliness can increase risk of cardiovascular disease, dementia, stroke, depression and anxiety.

Biological Mechanisms and Environmental Restoration

Louise Chawla, an environmental psychologist and professor emerita at CU Boulder who co-authored related research with Litt, emphasized the impact of natural environments. Engaging with nature, with its vivid sounds, smells and sights, can act as an “additional facilitator,” augmenting therapeutic benefits.

Future Integration into Public Health Frameworks

“We have nature in our cities and investment in our green infrastructure,” Litt stated, outlining the goal to bridge municipal environmental resources with formal healthcare delivery. Establishing this structural connection remains essential to delivering person-centered care that leverages natural environments for healing and wellbeing.

More on this story: Tulane Study Links Loneliness and Isolation to Lost Healthy Years

References

• Coll-Planas, L., et al. (2026). The Lancet Regional Health – Europe. DOI: 10.1016/j.lanepe.2026.101821