Subclinical responses in healthy cyclists briefly exposed to traffic-related air pollution: an intervention study

• Main Authors: Bernard Alfred, Degraeuwe Bart, Meeusen Romain, de Geus Bas, Nawrot Tim S, Jacobs Lotte, Sughis Muhammad, Nemery Benoit, Panis Luc
• Format: Article
• Language: English
• Published: BMC 2010-10-01
• Series: Environmental Health
• Online Access: http://www.ehjournal.net/content/9/1/64

<p>Abstract</p> <p>Background</p> <p>Numerous epidemiological studies have demonstrated adverse health effects of a sedentary life style, on the one hand, and of acute and chronic exposure to traffic-related air pollution, on the other. Because physical exercise augments the amount of inhaled pollutants, it is not clear whether cycling to work in a polluted urban environment should be encouraged or not. To address this conundrum we investigated if a bicycle journey along a busy commuting road would induce changes in biomarkers of pulmonary and systematic inflammation in a group of healthy subjects.</p> <p>Methods</p> <p>38 volunteers (mean age: 43 ± 8.6 years, 26% women) cycled for about 20 minutes in real traffic near a major bypass road (road test; mean UFP exposure: 28,867 particles per cm³) in Antwerp and in a laboratory with filtered air (clean room; mean UFP exposure: 496 particles per cm³). The exercise intensity (heart rate) and duration of cycling were similar for each volunteer in both experiments. Exhaled nitric oxide (NO), plasma interleukin-6 (IL-6), platelet function, Clara cell protein in serum and blood cell counts were measured before and 30 minutes after exercise.</p> <p>Results</p> <p>Percentage of blood neutrophils increased significantly more (p = 0.004) after exercise in the road test (3.9%; 95% CI: 1.5 to 6.2%; p = 0.003) than after exercise in the clean room (0.2%; 95% CI: -1.8 to 2.2%, p = 0.83). The pre/post-cycling changes in exhaled NO, plasma IL-6, platelet function, serum levels of Clara cell protein and number of total blood leukocytes did not differ significantly between the two scenarios.</p> <p>Conclusions</p> <p>Traffic-related exposure to particles during exercise caused a small increase in the distribution of inflammatory blood cells in healthy subjects. The health significance of this isolated change is unclear.</p>