Why Your Brain Needs a Walk in the Park: Residential Greenspaces as the Next Frontier in Brain Research and Treatment

This editorial frames residential greenspaces—parks, gardens, and other neighborhood green areas—as an important and expanding frontier in clinical and behavioral neuroscience. Building on early 20th-century work linking greenspace and health, the authors highlight the rapidly growing evidence base (nearly a thousand studies by mid-2024) connecting greenspace exposure with brain structure and function across the lifespan. The purpose is to synthesize emerging findings, emphasize their relevance to brain health and neurodegenerative risk, and call for refined methodologies to strengthen causal inference and inform public health and urban planning.

The editorial synthesizes observational and cohort evidence showing positive associations between residential greenspace and brain outcomes. In adults and children, proximity to greenspace relates to larger total brain, gray matter, and white matter volumes; in children, exposure improves attention (faster reaction times for sustained and selective attention), short-term memory, and visual processing, while reduced neighborhood greenspace correlates with poorer spatial working memory regardless of deprivation status. In older adults, increased greenspace prior to MRI is linked to borderline reductions in ventricular enlargement, with no consistent effects on other imaging measures or interactions by APOE genotype or sex. Greater greenspace exposure is associated with reduced risks of Alzheimer’s disease and vascular dementia; forest greenspace correlates with lower mild cognitive impairment risk, and greenspace diversity with reduced dementia incidence. Reported magnitudes include a 24% lower dementia risk with increased residential greenspace (attenuated after adjustment) and a 28% lower risk at medium greenspace levels. Greenspace also associates with reduced severe stroke risk, and large-scale cohorts (e.g., >422,000 participants followed for 12.5 years) show lower risks of stroke, dementia, and comorbidities, with strongest protective effects within the first year that persist for years. Among >61 million Medicare beneficiaries, higher vegetation by NDVI relates to reduced Alzheimer’s and related dementias hospitalizations; for Parkinson’s disease, higher NDVI and park coverage link to lower hospitalization rates, with demographic heterogeneity. Socioeconomic context modifies effects: neighborhoods with lower greenspace and income exhibit more pronounced worsening in white matter grade compared to higher greenspace/high-income areas.

• Residential greenspace is positively associated with larger brain volumes (total, gray, white matter) in adults and children. • In children, greenspace exposure improves attention (faster reaction times for sustained and selective attention), enhances short-term memory, and quickens visual processing; reduced greenspace is linked to poorer spatial working memory across socioeconomic strata. • In older adults, increased greenspace prior to MRI relates to borderline reductions in ventricular enlargement, with no significant effects on other MRI measures or by APOE genotype/sex. • Higher greenspace exposure associates with reduced risks of Alzheimer’s disease and vascular dementia; forest greenspace links to lower mild cognitive impairment risk; greater greenspace diversity correlates with reduced dementia risk. • Quantitatively, increased residential greenspace is associated with a 24% lower dementia risk (attenuated after adjustment), and medium greenspace levels with a 28% lower dementia risk. • Greater residential greenspace associates with reduced severity of ischemic stroke. • In a cohort of over 422,000 participants followed for 12.5 years, increased greenspace is linked to lower risks of stroke, dementia, and comorbid conditions, with strong protective effects in the first year that persist for several years. • Among more than 61 million Medicare beneficiaries, higher NDVI (vegetation) is associated with reduced ADRD hospitalizations; for Parkinson’s disease, higher NDVI and park coverage are linked to lower hospitalization rates, with effects varying by demographics. • Socioeconomic disparities intersect with greenspace: lower greenspace and income are associated with more pronounced white matter grade worsening.

The compiled evidence suggests residential greenspaces may contribute meaningfully to brain health across the lifespan by supporting cognitive function, lowering risks of neurodegenerative diseases and stroke, and potentially mediating environmental exposures such as air pollution. These associations, while largely correlational, point to greenspace as a modifiable environmental factor with public health relevance. The editorial underscores that clarifying causal pathways and mechanisms—potentially involving neuroinflammation, oxidative stress, and neuroplasticity—could strengthen the case for greenspace-focused interventions. Integrating standardized and nuanced exposure metrics and comprehensive confounder control is critical to translate these findings into urban design and policy that target cognitive health and disease prevention.

Residential greenspaces emerge as a promising and underutilized avenue in brain research and treatment. The editorial advocates for advancing the field through standardized greenspace exposure metrics, detailed geospatial analyses, user-centered assessments of quality and accessibility, and stronger causal designs (longitudinal and experimental). It calls for mechanistic studies at molecular and cellular levels to elucidate how greenspace influences brain health, and for integrated environmental and individual health data to provide holistic insights. These efforts can inform urban planning and targeted public health interventions to optimize cognitive function and reduce neurological disease burden.

Current greenspace research is limited by variability in definitions and measurement across studies; reliance on indirect exposure metrics (e.g., satellite NDVI, self-report) that may not capture quality or usability; predominance of correlational data from cohort designs; and challenges in fully accounting for confounding factors such as socioeconomic status, air quality, and lifestyle. These constraints impede causal inference and generalizability.