Graduate School of Human Development and Environment, Kobe University, Kobe, Hyogo, Japan.
Department of Preventive Gerontology, National Center for Geriatrics and Gerontology, Obu, Aichi, Japan.
Geriatr Gerontol Int. 2017 Oct;17(10):1455-1462. doi: 10.1111/ggi.12895. Epub 2016 Sep 16.
Objective measurements of outdoor time are essential to establishing evidence about the health benefits of going outdoors among older adults. To better understanding the health benefits of going outdoors, clarification of potential mediators to connect going outdoors with health benefits is necessary. The present study aimed to investigate associations of objectively-measured outdoor time with older adults' physical and psychological function, and examine the mediating role of physical activity on these associations.
Baseline data from a randomized control trial of physical activity among older adults with global cognitive impairment was used. Data from 192 participants were analyzed. Measures included steps-per-day, objectively-measured outdoor time per day using global positioning systems, physical function (cardiorespiratory fitness, lower-extremity strength), psychological function (depression, well-being) and basic factors.
Path analysis showed that outdoor time was significantly associated with steps-per-day (path coefficient = 0.23) and depression (path coefficient = -0.16). Outdoor time was not directly associated with cardiorespiratory fitness, lower-extremity strength and well-being. However, steps-per-day was associated with cardiorespiratory fitness (path coefficient = 0.18), lower-extremity strength (path coefficient = -0.22) and well-being (path coefficient = 0.14).
We found that objectively-measured outdoor time was indirectly associated with physical function, and both directly and indirectly with psychological function through physical activity among older adults. This finding indicates that going outdoors influences older adults' health outcomes, and is mainly mediated by physical activity. Geriatr Gerontol Int 2017; 17: 1455-1462.
客观测量户外活动时间对于确定老年人户外活动对健康的益处至关重要。为了更好地了解户外活动的健康益处，有必要阐明潜在的中介因素，将户外活动与健康益处联系起来。本研究旨在调查老年人客观测量的户外活动时间与身体和心理功能之间的关联，并检验身体活动在这些关联中的中介作用。
本研究使用了一项针对伴有全球认知障碍的老年人进行身体活动的随机对照试验的基线数据。共分析了 192 名参与者的数据。测量包括每天的步数、使用全球定位系统测量的每天户外活动时间、身体功能（心肺适能、下肢力量）、心理功能（抑郁、幸福感）和基本因素。
路径分析显示，户外活动时间与每天的步数（路径系数=0.23）和抑郁（路径系数=-0.16）呈显著相关。户外活动时间与心肺适能、下肢力量和幸福感无直接关联。然而，每天的步数与心肺适能（路径系数=0.18）、下肢力量（路径系数=-0.22）和幸福感（路径系数=0.14）呈显著相关。
我们发现，客观测量的户外活动时间与老年人的身体功能呈间接相关，通过身体活动与心理功能呈直接和间接相关。这一发现表明，户外活动影响老年人的健康结果，主要通过身体活动来介导。
