Nearby Green Space Linked To Reduced Dementia Risk

A 2025 study in Communications Medicine examined whether outdoor physical activity and living near green spaces affect the risk of developing dementia. Dementia is a major global health concern, and previous research suggested that exercise and nature exposure could help protect brain health, but the long-term impact of outdoor activity combined with access to green spaces was unclear.

To investigate this impact, the researchers analyzed data from 187,724 adults aged 60 to 73 in the UK Biobank who reported how much physical activity they did outdoors. Scientists also calculated the amount of green space within about 300 meters of each participant’s home, which for the purposes of the study was considered an accessible walking distance. Health records were followed for about 13 years to track new cases of dementia. A subgroup of over 36,000 participants had brain scans measuring hippocampal and total gray-matter volumes and white-matter hyperintensities, which are markers linked to brain health. The analysis accounted for age, sex, education, smoking, health conditions, neighborhood deprivation, air pollution, and noise.

During follow-up, 7,218 participants developed dementia. Those with the highest levels of outdoor activity had about a 16 percent lower overall risk of dementia compared with the least active participants. The protective effect was strongest for vascular dementia and weaker (but still present) for Alzheimer’s disease. People who lived near more green space experienced even greater benefits from outdoor activity, suggesting that environment amplifies the effect. Brain imaging showed that higher outdoor activity was associated with larger hippocampal and total gray-matter volumes and fewer white-matter hyperintensities, which may help explain how activity and green space contribute to better brain health.

The study highlights that being active outdoors and having access to green areas are linked to measurable reductions in dementia risk and structural brain benefits. The authors suggest that promoting outdoor exercise and designing communities with accessible nature could be effective strategies to support healthy brain aging. The research provides evidence that both lifestyle and environment matter for preventing dementia and maintaining brain health over time.