The effect of pre-exercise diesel exhaust exposure on cycling performance and cardio-respiratory variables

Abstract

Purpose: To determine the effect of pre-exercise exposure to diesel exhaust (DE) on 20-km cycling performance, pulmonary function, and cardio-respiratory variables during exercise.

Methods: Eight endurance-trained males participated in the study. Test days consisted of a 60-min exposure to either filtered air (FA) or DE, followed by a 20 km cycling time trial. Exposures to DE were at a concentration of 300 µg/m³ of PM_2.5. Forced expiratory volume in 1 s (FEV₁) and forced vital capacity (FVC) were measured before and after exposure, and after exercise. Oxygen consumption (VO₂) and carbon dioxide production (VCO₂), minute ventilation (V_E), tidal volume (V_T), breathing frequency (F_B), heart rate and oxyhemoglobin saturation (SpO₂), were collected during the time trials. The effect of condition on time trial duration, an order effect, and mean cardio-respiratory variables were each analysed using paired T-tests. Repeated-measures ANOVA were used to assess the effect of DE exposure on pulmonary function.

Results: There was a main effect of condition (FA vs. DE) on the change in FEV₁ from baseline, and in exercise heart rate. Post hoc tests revealed that exercise-induced bronchodilation was significantly attenuated following DE compared to FA. There were no main effects of condition on 20 km cycling performance, or VO₂, VCO₂, V_E, V_T, F_B and SpO₂ during a 20 km time trial.

Conclusion: A 60-min exposure to DE prior to exercise significantly attenuated exercise-induced bronchodilation and significantly increased heart rate during exercise. Pre-exercise exposure to diesel exhaust did not significantly impair 20 km cycling time trial performance.

Keywords::

• Air pollution
• exercise performance
• heart rate
• particulate matter
• pulmonary function

Acknowledgements

The Authors would like to thank the Canadian Academy of Sport and Exercise Medicine and the Fraser Basin Council BC Clean Air Research Fund (BC CLEAR) for financial support for this investigation.

Declaration of interest

This work was funded by the Canadian Academy of Sport and Exercise Medicine and the Fraser Basin Council BC Clean Air Research Fund (BC CLEAR).