Air pollution and elite adolescent soccer players' performance and well-being; an observational study.

Introduction: Exercising outdoors may inadvertently lead to individuals inhaling levels of air pollution that may be detrimental to their health and activity-related performance. Endurance athletes are a particularly susceptible subgroup due to their high ventilation rates sustained over prolonged periods of time coupled with high training loads that often occur outdoors. In this study, we estimate the effects of air pollution on a series of athletic performance parameters in an elite adolescent soccer team.

Methods: External, internal, and subjective loads and wellness questionnaires were recorded for the 26 matches and 197 training sessions carried out during the 2018-19 season for a U19 team competing in Germany. Each session was combined with hourly information on the concentration of PM, O and NO in spatial proximity to each playing field for the duration of training or playing.

Results: Increases in PM and O had significant (p <.001) associations with decreasing total distance (m) ran per session. Furthermore, increases in O and NO concentrations were related to an increase in average heart rate (p <.05). Moreover, increases in PM concentration was associated with increased rating of perceived exertion (p <.001). Last, the total inhaled dose of O and NO over one session was linked to significant (p <.05) decreases in athletes' wellness scores on the following morning.

Discussion: We find supporting evidence of the negative effects of air pollution in elite adolescent soccer players in both matches and training. The negative impacts observed on several aspects of performance are present within an elite team that regularly trained in pollution levels well within the normal ranges of what the World Health Organisation (WHO) reports to be suitable air quality. Therefore, mitigation strategies such as monitoring the air quality at the training pitch are recommended to reduce athlete exposure to air pollution even when exercising in moderate air quality.