Division of Epidemiology, Institute for Health and Equity, Medical College of Wisconsin, 8701 Watertown Plank Road, P.O. Box 26509, Milwaukee, WI, 53226-0509, USA.
Division of Biostatistics, Institute for Health and Equity, Medical College of Wisconsin, 8701 Watertown Plank Road, P.O. Box 26509, Milwaukee, WI, 53226-0509, USA.
J Behav Med. 2018 Aug;41(4):494-503. doi: 10.1007/s10865-018-9911-1. Epub 2018 Jan 30.
Chronic diseases-including cancer, cardiovascular diseases, and metabolic conditions such as diabetes and obesity-account for over 60% of overall global mortality. Sedentary time increases the risk for chronic disease incidence and mortality, while moderate to vigorous physical activity is known to decrease risk. Most Americans spend at least half of their time sedentary, with a trend toward increasingly sedentary lifestyles, and few Americans achieve recommended levels of physical activity. Time spent outdoors has been associated with reduced sedentary time and increased physical activity among children/youth and the elderly, but few population-based studies have examined this relationship among working age adults who may face greater constraints on active, outdoor time. This study examines the relationship between time spent outdoors, activity levels, and several chronic health conditions among a population-based sample of working age American adults in the National Health and Nutrition Examination Survey (NHANES) for 2009-2012. Findings provide evidence that time spent outdoors, on both work days and non-work days, is associated with less time spent sedentary and more time spent in moderate to vigorous physical activity. Further, findings indicate that time spent outdoors is associated with lower chronic disease risk; while these associations are partially explained by activity levels, controlling for activity levels does not fully attenuate the relationship between time outdoors and chronic disease risk. While cross-sectional, study findings support the notion that increasing time spent outdoors could result in more active lifestyles and lower chronic disease risk. Future work should examine this relationship longitudinally to determine a causal direction. Additional work is also needed to identify mechanisms beyond physical activity, such as psychosocial stress, that could contribute to explaining the relationship between time spent outdoors and chronic disease risk.
慢性疾病——包括癌症、心血管疾病和代谢疾病，如糖尿病和肥胖——占全球总死亡率的 60%以上。久坐时间增加了慢性病发病和死亡的风险，而适度到剧烈的身体活动已知可以降低风险。大多数美国人至少有一半的时间处于久坐状态，而且久坐的生活方式呈上升趋势，很少有美国人达到推荐的身体活动水平。户外活动时间与儿童/青少年和老年人减少久坐时间和增加身体活动有关，但很少有基于人群的研究调查了这种关系在工作年龄成年人中，他们可能面临更大的限制，积极的，户外时间。本研究调查了在全国健康和营养检查调查（NHANES）中，工作年龄的美国成年人在户外时间、活动水平与几种慢性健康状况之间的关系，该调查时间为 2009-2012 年。研究结果表明，无论是工作日还是非工作日，在户外的时间与久坐时间减少和中高强度体力活动时间增加有关。此外，研究结果表明，在户外的时间与较低的慢性疾病风险有关；虽然这些关联部分可以通过活动水平来解释，但控制活动水平并不能完全减弱户外活动时间与慢性疾病风险之间的关系。尽管这是一项横断面研究，但研究结果支持了这样一种观点，即增加在户外的时间可能会导致更积极的生活方式和降低慢性疾病的风险。未来的工作应该从纵向角度来研究这种关系，以确定因果关系。还需要进一步研究除了身体活动之外的其他机制，例如心理社会压力，这些机制可能有助于解释户外活动时间与慢性疾病风险之间的关系。
