Associations between air pollution and cardio-respiratory physiological measures in older adults exercising outdoors

We examined whether exercising indoors vs. outdoors reduced the cardio-respiratory effects of outdoor air pollution. Adults ≥55 were randomly assigned to exercise indoors when the Air Quality Health Index was ≥5 and outdoors on other days (intervention group, n = 37), or outdoors everyday (control group, n = 35). Both groups completed cardio-respiratory measurements before and after exercise for up to 10 weeks. Data were analyzed using linear mixed effect regression models. In the control group, an interquartile range increase in fine particulate matter (PM_2.5) was associated with increases of 1.4% in heart rate (standard error (SE) = 0.7%) and 5.6% (SE = 2.6%) in malondialdehyde, and decreases of 5.6% (SE = 2.5%) to 16.5% (SE = 7.5%) in heart rate variability measures. While the hypothesized benefit of indoor vs. outdoor exercise could not be demonstrated due to an insufficient number of intervention days (n = 2), the study provides evidence of short-term effects of air pollution in older adults. ISRCTN #26552763.

本研究旨在考察室内运动与室外运动是否可减轻室外空气污染所引发的心肺效应。本研究纳入年龄≥55岁的成年人，将其随机分为两组：当空气质量健康指数（Air Quality Health Index）≥5时于室内运动、其余时日于室外运动的干预组（n=37），以及每日均于室外运动的对照组（n=35）。两组受试者均在运动前后完成心肺相关指标检测，随访周期最长达10周。研究采用线性混合效应回归模型对数据进行分析。结果表明，对照组中细颗粒物（fine particulate matter, PM₂.₅）的四分位距升高与心率升高1.4%（标准误（standard error, SE）=0.7%）、丙二醛水平升高5.6%（SE=2.6%）相关，同时与心率变异性（heart rate variability）指标降低5.6%（SE=2.5%）至16.5%（SE=7.5%）相关。尽管因干预天数过少（n=2），无法证实室内运动相较于室外运动的预设获益，但本研究仍为老年人群中空气污染的短期效应提供了实证支持。试验注册号：ISRCTN #26552763。