The pulmonary and autonomic effects of high-intensity and low-intensity exercise in diesel exhaust.
BACKGROUND
Exposure to air pollution impairs aspects of pulmonary and autonomic function and causes pulmonary inflammation. However, how exercising in air pollution affects these indices is poorly understood. Therefore, the purpose of this study was to determine the effects of low-intensity and high-intensity cycling with diesel exhaust (DE) exposure on pulmonary function, heart rate variability (HRV), fraction of exhaled nitric oxide (FeNO), norepinephrine and symptoms.


METHODS
Eighteen males performed 30-min trials of low-intensity or high-intensity cycling (30 and 60% of power at VO2peak) or a resting control condition. For each subject, each trial was performed once breathing filtered air (FA) and once breathing DE (300μg/m3 of PM2.5, six trials in total). Pulmonary function, FeNO, HRV, norepinephrine and symptoms were measured prior to, immediately post, 1 h and 2 h post-exposure. Data were analyzed using repeated-measures ANOVA.


RESULTS
Throat and chest symptoms were significantly greater immediately following DE exposure than following FA (p < 0.05). FeNO significantly increased 1 h following high-intensity exercise in DE (21.9 (2.4) vs. 19.3 (2.2) ppb) and FA (22.7 (1.7) vs. 19.9 (1.4)); however, there were no differences between the exposure conditions. All HRV indices significantly decreased following high-intensity exercise (p < 0.05) in DE and FA. The exception to this pattern was LF (nu) and LF/HF ratio, which significantly increased following high-intensity exercise (p < 0.05). Plasma norepinephrine (NE) significantly increased following high-intensity exercise in DE and FA, and this increase was greater than following rest and low-intensity exercise (p < 0.05). DE exposure did not modify any effects of exercise intensity on HRV or norepinephrine.


CONCLUSIONS
Healthy individuals may not experience greater acute pulmonary and autonomic effects from exercising in DE compared to FA; therefore, it is unclear if such individuals will benefit from reducing vigorous activity on days with high concentrations on particulate matter.
['Giles|Luisa V|LV|', 'Carlsten|Christopher|C|', 'Koehle|Michael S|MS|']
D000293:Adolescent D000328:Adult D000393:Air Pollutants D015444:Exercise D006339:Heart Rate D006801:Humans D019570:Inhalation Exposure D008297:Male D009569:Nitric Oxide D009638:Norepinephrine D012143:Respiratory Physiological Phenomena D001335:Vehicle Emissions D055815:Young Adult
Exercise Air pollution Pulmonary function FeNO Norepinephrine Exercise intensity