Changes in objectively measured outdoor time and physical, psychological, and cognitive function among older adults with cognitive impairments

BACKGROUND: Older adults with cognitive impairment are at higher risk for various health problems. Although previous studies have suggested going outdoors more frequently might be effective to promote health, no longitudinal studies have examined objectively measured outdoor time in this population. This study examined the relationships between changes in objectively measured outdoor time and physical, psychological, and cognitive functions among older adults with cognitive impairments. METHODS: This study was a secondary analysis of a randomized controlled trial (n = 145). The baseline and 1-year follow-up data of outdoor time per day measured by the global positioning system, physical functions (6-minute walk test, 5-repetition chair stand test), psychological functions (Geriatric Depression Scale, simplified World Health Organization Five Well-being Index), and cognitive functions (tablet versions of the Trail-making Test, Symbol Digit Substitution Test, Word Memory Test, Story Memory Test) were used. RESULTS: Multiple regression analyses revealed that changes in outdoor time were significantly associated with changes in 6-minute walk (standardized beta = 0.20, p = 0.048) and 5-repetition chair stand tests (standardized beta = -0.19, p = 0.032) after adjusting for baseline data, basic factors, and trial allocation. However, significant relationships between changes in outdoor time and psychological and cognitive functions were not revealed. CONCLUSIONS: The results indicate that maintaining or increasing outdoor time would be effective to prevent declines in physical functions but that a quantitative aspect of going outdoors would have limited impact on psychological and cognitive functions among older adults with cognitive impairment.