The review, led by Furqan Butt and colleagues at the University of Birmingham with collaborators at Keele University, the University of Warwick and other institutions, set out to synthesise the quantitative evidence on green health prescribing and nature-based interventions for adults aged 50 and over in primary care and community settings. The team followed Cochrane Handbook guidance, reported the work according to PRISMA and SWiM standards, and graded the certainty of findings using an approach informed by GRADE, the framework widely regarded as the gold standard for judging how much confidence can be placed in medical evidence. The review was registered prospectively on PROSPERO, and patient and public contributors with lived experience of nature-based programmes helped shape the design and interpretation throughout.

The search was exhaustive by any reasonable measure. An information specialist ran searches across MEDLINE, PsycINFO, ASSIA, GreenFILE, Web of Science and Dimensions, covering publications from 2000 through October 2024, supplemented by grey literature searches via Overton and Google. That trawl produced 12,520 unique records. After independent double-screening of titles and abstracts, 230 papers went forward to full-text assessment, and just 41 proved eligible for the wider evidence review. Of these, 21 studies reported quantitative data on the effectiveness of green health prescribing or nature-based interventions and formed the core of the synthesis. The attrition alone tells a story: the vast majority of published work in this field either lacks a natural environment component, studies younger populations, or fails to evaluate an intervention in a way that permits meaningful appraisal.

The 21 included studies comprised 11 randomised controlled trials, including one cluster-randomised trial and two pilot trials, alongside seven quasi-experimental non-randomised designs and three single-arm before-and-after studies. Together they evaluated four broad categories of intervention: activities in nature such as forest therapy, wetland walks and blue space exposure; structured exercise in green spaces, including park prescriptions; horticultural therapy programmes; and indoor gardening adapted for nursing home residents and people with mobility limitations. Collectively they involved roughly 1,300 participants, spanning community-dwelling older adults and people in residential care, including some living with dementia. Yet a striking detail emerges from the study characteristics: in only four of the 21 studies was the intervention actually prescribed by a health or care professional. The rest recruited participants directly through community organisations or research channels, which raises real questions about how well the findings apply to genuine clinical referral pathways.

The results, synthesised narratively because the heterogeneity of participants, interventions and outcome measures made meta-analysis inappropriate, paint a picture of tantalising but fragile signals. Many studies reported improvements in at least one health or wellbeing outcome, and the review identified potential benefits for quality of life, mental health, physical function, fatigue, loneliness and social connectedness. For activities in nature, involving 270 participants across six studies, improvements compared with control were observed in quality of life, anxiety and social functioning among people with long-term conditions, although results for blood pressure and depression were inconsistent, and one trial of post-cancer patients found that an indoor relaxation group actually reported greater reductions in fatigue than a nature walking group. For green space exercise, three randomised trials totalling 221 participants showed little convincing effect; systolic blood pressure, the only outcome informed by two trials, showed small and non-significant differences against usual care or indoor exercise.

The horticultural and indoor gardening evidence was somewhat more encouraging, particularly on social outcomes. Four indoor gardening studies, all rated low risk of bias and involving 310 participants, suggested improvements in overall quality of life and loneliness among nursing home residents, earning moderate-certainty GRADE ratings, the highest awarded anywhere in the review. Among nine horticultural intervention studies with 504 participants, statistically significant benefits emerged for self-efficacy and self-esteem, social connectedness, and activities of daily living, with individual trials reporting gains in these domains compared with waitlist or usual-care controls. But for most other outcomes, including wellbeing, cognitive function, psychological health and physiological measures, the findings were inconsistent, small, or not statistically significant, and the certainty of evidence was rated low or very low across the board.

Why does the evidence fall so short of the enthusiasm? The review authors point to a familiar cluster of methodological weaknesses. Sample sizes were typically small, often fewer than 50 participants per arm, leaving individual trials underpowered to detect meaningful differences. Follow-up was usually short, frequently limited to assessments immediately after the programme ended, so nothing can be said about whether any benefits persist. Blinding of outcome assessors was often absent, and many non-randomised studies struggled with incomplete outcome data and inadequate control of confounding. Perhaps most fundamentally, the interventions themselves were extraordinarily diverse, ranging from guided forest bathing to indoor herb cultivation, delivered in settings from care homes to wetlands, against comparators as varied as printed educational materials, art therapy and structured exercise. This heterogeneity defeated not only meta-analysis but also the planned subgroup analyses by deprivation level, geography and age band.

There is also a glaring equity gap. The review had hoped to examine whether green prescribing works particularly well, or particularly poorly, for older people in economically deprived communities, a question of real policy weight given that a survey of Scottish general practitioners found 80 per cent were willing to refer patients to green social prescribing but worried about accessibility for patients from disadvantaged areas. Very few included studies reported socioeconomic data at all, leaving the review unable to draw any conclusion about whether unequal access to safe, well-maintained green space shapes outcomes for the very populations that social prescribing is often meant to reach. Meanwhile, the funding and policy momentum continues: in 2024, one million pounds in green social prescribing grants was awarded to NHS charities in the United Kingdom, and implementation has been expanding across the country.

Interestingly, the gap between trial evidence and lived experience was one of the most striking findings. The public contributors involved in the review, including service users who had participated in nature-based programmes, consistently reported positive impacts on their mental and physical health. They emphasised connection with nature, social interaction, and a sense of meaning and purpose derived from these activities, and highlighted spiritual and psychosocial dimensions that they felt standard outcome measures fail to capture. They also valued green outdoor environments as venues for strengthening community cohesion in ways that traditional clinical settings cannot match. This disconnect between what patients say they gain and what small, short, heterogeneous trials can statistically detect is a recurring challenge in evaluating complex, person-centred interventions, and it does not necessarily mean the benefits are illusory; it may mean the measurement tools and study designs are inadequate to the task.

The review’s conclusions are measured but pointed. The available evidence remains limited in volume, heterogeneous in design and predominantly of low to very low certainty, and there is currently insufficient robust evidence to support widespread implementation of green health prescribing within routine care. Crucially, almost no studies evaluated prescribing itself, as a referral option delivered by primary care clinicians, rather than a specific activity offered directly to participants. The authors call for high-quality pragmatic trials, potentially using cluster or stepped-wedge designs, and implementation studies that evaluate green prescribing at the service level, with standardised outcome measures, longer follow-up, attention to cost-effectiveness and healthcare resource use, and deliberate focus on older adults with long-term conditions and those living in deprivation. As the World Health Organization identifies loneliness as a global health challenge and health systems search for scalable, preventative solutions, nature-based interventions may yet earn a firm place in the clinical toolkit. For now, however, the prescription is written more in hope than in hard evidence, and the task for researchers is to change that before policy outruns the science entirely.

Subject of Research: Effectiveness of green health prescribing and nature-based interventions for older adults in primary and community care

Article Title: Effectiveness of green health prescribing and nature-based interventions in primary care and community settings for older adults: a systematic review of health, wellbeing and social outcomes

Article References: Effectiveness of green health prescribing and nature-based interventions in primary care and community settings for older adults: a systematic review of health, wellbeing and social outcomes. (n.d.). https://doi.org/10.1186/s12916-026-05194-z

Image Credits: AI Generated

DOI: 10.1186/s12916-026-05194-z

Keywords: green health prescribing, nature-based interventions, older adults, social prescribing, horticultural therapy, primary care, systematic review, quality of life, loneliness, healthy ageing, mental health, evidence certainty