Petrella Robert J, Kennedy Emily, Overend Tom J
Faculties of Medicine and Health Sciences, University of Western Ontario, London, Ontario, Canada.
Environ Health Insights. 2008 Oct 1;1:51-62. doi: 10.4137/ehi.s820.
Evidence is unequivocal that exercise training can improve health outcomes. However, despite this evidence, adoption of healthy lifestyles is poor. The physical environment is one possible determinant of successful adoption of healthy lifestyles that could influence outcomes in community-based intervention strategies. We developed a novel exercise prescription delivered in two different cohorts of older sedentary adults-one delivered by family physicians to patients with identified cardiovascular risk factors (CRF) and the other delivered at a community exercise facility to a larger cohort of healthy sedentary adults (HSA). We then determined whether the place of residence and proximity to facilities promoting physical activity and healthy or unhealthy eating could influence clinical changes related to these community-based exercise prescriptions.
Two different cohorts of older patients were administered similar exercise prescriptions. The CRF cohort was a sedentary group of 41 older adults with either high-normal blood pressure (120-139 mmHg/85-89 mmHg) or impaired glucose tolerance (fasting glucose 6.1-6.9 mmol/l) who were prescribed exercise by their family physicians at baseline and followed over 12 months. The HSA cohort consisted of 159 sedentary older adults who were prescribed a similar exercise prescription and then participated in a chronic training program over 5 years at a community-based training facility. Outcomes of interest were change in fitness (VO(2max)), resting systolic blood pressure (rSBP) and body mass index (BMI). GIS-determined shortest distance to local facilities promoting physical activity and healthy versus unhealthy were compared at baseline and followup using simple logistic regression. Those subjects in CRF group were further identified as responders (exhibited an above average change in VO(2max)) and were then compared to non-responders according to their patterns of proximity to physical activity and eating facilities.
In the CRF cohort at baseline, greater GIS-distance to golf courses correlated with higher rSBP (r = 0.38, p = 0.02) while greater distance to bike paths correlated with greater BMI (r = 0.32, p = 0.05). CRF responders who lived closer to a park had higher BMI (r = -0.46, p = 0.05) while no other relationship among responders and proximity to either physical activity or eating facilities was observed. CRF non-responders lived closer to formal physical activity facilities (community centres) and higher fat eating facilities. In the HSA cohort, higher fitness was correlated with greater distance to both formal and informal physical activity facilities (baseball fields or dance studios) while this was also correlated with a higher rSBP (r = 0.17, p = 0.04). In general, physical activity facilities were often located near higher-fat eating facilities regardless of cohort.
Those prescribed exercise by their family physician for the presence of health risk tended to closer to any type of physical activity facility compared to those who joined an exercise program on their own. A positive response to the intervention at 12 months was associated with closer access to informal physical activity facilities while non-responders lived closer to both types of physical activity facility as well as high fat eating facilities. In contrast, healthy chronic exercise trainees in the community did not show any meaningful relation between fitness and proximity to healthy lifestyle facilities. Hence, the access to facilities is not as important to those who adopt physical activity on their own whereas those targeted by physicians may be influenced by access. Furthermore, the response or lack thereof to exercise interventions in those at risk may be influenced by proximity to both physical activity and unhealthy eating facilities.
有明确证据表明运动训练可改善健康状况。然而，尽管有此证据，健康生活方式的采用情况却不容乐观。物理环境是成功采用健康生活方式的一个可能决定因素，它可能会影响基于社区的干预策略的效果。我们为两组久坐不动的老年人制定了一种新颖的运动处方，一组由家庭医生为已确定有心血管危险因素（CRF）的患者开具，另一组在社区健身设施为更大规模的健康久坐成年人（HSA）开具。然后，我们确定居住地点以及与促进身体活动和健康或不健康饮食的设施的距离是否会影响与这些基于社区的运动处方相关的临床变化。
为两组不同的老年患者开具了相似的运动处方。CRF组是41名久坐不动的老年人，他们要么血压处于高正常范围（120 - 139 mmHg/85 - 89 mmHg），要么糖耐量受损（空腹血糖6.1 - 6.9 mmol/l），在基线时由家庭医生开具运动处方，并随访12个月。HSA组由159名久坐不动的老年人组成，他们被开具了相似的运动处方，然后在社区训练设施参加了为期5年的长期训练项目。感兴趣的结果包括体能变化（最大摄氧量（VO₂max））、静息收缩压（rSBP）和体重指数（BMI）。在基线和随访时，使用简单逻辑回归比较通过地理信息系统（GIS）确定的到促进身体活动和健康与不健康的当地设施的最短距离。CRF组中的那些受试者进一步被确定为有反应者（最大摄氧量（VO₂max）变化高于平均水平），然后根据他们与体育活动和饮食设施的接近模式与无反应者进行比较。
在CRF组基线时，到高尔夫球场的GIS距离越大，rSBP越高（r = 0.38，p = 0.02），而到自行车道的距离越大，BMI越高（r = 0.32，p = 0.05）。居住在离公园较近的CRF有反应者BMI较高（r = -0.46，p = 0.05），而在有反应者中未观察到与体育活动或饮食设施的接近程度有其他关系。CRF无反应者居住在离正规体育活动设施（社区中心）和高脂肪饮食设施较近的地方。在HSA组中，体能越高与到正规和非正规体育活动设施（棒球场或舞蹈工作室）的距离越大相关，同时这也与较高的rSBP相关（r = 0.17，p = 0.04）。总体而言，无论在哪一组，体育活动设施通常都位于高脂肪饮食设施附近。
与自行参加运动项目的人相比，因存在健康风险而由家庭医生开具运动处方的人往往离任何类型的体育活动设施更近。对12个月干预的积极反应与更接近非正规体育活动设施相关，而无反应者居住在离两种类型的体育活动设施以及高脂肪饮食设施都更近的地方。相比之下，社区中的健康长期运动训练者在体能与接近健康生活方式设施之间未显示出任何有意义的关系。因此，对于自行进行体育活动的人来说，获得设施的机会并不那么重要，而医生针对的人群可能会受到获得设施机会的影响。此外，有风险人群对运动干预的反应或无反应可能会受到与体育活动和不健康饮食设施的接近程度的影响。
