Higher Fine Particulate Matter and Temperature Levels Impair Exercise Capacity
What are associations between changes in ambient fine particulate matter (PM2.5) air pollution and variations in ambient temperature (T) with directly measured aerobic performance outcomes during cardiopulmonary exercise (CPX) testing among patients initiating cardiac rehabilitation?
This was a cross-sectional observational study performed among 2,078 patients enrolling into a cardiac rehabilitation program at the University of Michigan (from January 2003 to August 2011). CPX results were reviewed retrospectively. The main aim was to determine the effect of short-term changes in ambient PM2.5 and T on directly measured peak exercise oxygen consumption. Other dependent variables were ventilatory threshold, peak exercise systolic blood pressure, and peak exercise heart rate. A monitoring site in Allen Park, Michigan, was used to determine PM2.5 and T levels. Multiple models were fitted to evaluate the effects of T and PM2.5 on the outcomes during CPX testing, while adjusting for relevant covariates.
Peak exercise oxygen consumption was significantly decreased by approximately 14.9% per 10 mcg/m3 increase in ambient PM2.5 levels. Elevations in PM2.5 were also related to decreases in ventilatory threshold and peak heart rate and increases in peak systolic blood pressure. A 10°C increase in temperature was associated with reductions in peak exercise oxygen consumption (20.6-27.3%). Throughout the entire time period, no daily mean exceeded current US National Ambient Air Quality Standard for 24 hours of 35 mcg/m3.
Elevations in PM2.5, within national air quality standards, were associated with detrimental changes in aerobic exercise capacity, as assessed by peak exercise oxygen consumption and other variables during CPX testing.
This is an interesting study that draws attention to the potentially deleterious impact of fine particulate matter air pollution and variations in ambient temperature among cardiac rehabilitation patients. As the authors posit, “Environmental exposures may be important risk factors at the public health level for impairment in aerobic exercise capacity.”
Keywords: Air Pollution, Blood Pressure, Environmental Exposure, Exercise, Health Status, Oxygen Consumption, Particulate Matter, Primary Prevention, Rehabilitation, Risk Factors, Temperature
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