Air pollution appears to decrease the performance of racehorses, the findings of a preliminary analysis suggest.
Associate Professor Oscar Araneda, in a paper just published in the journal Animals, has proposed using horse racing as a model to study the relationship between air pollutants and physical performance.
Araneda, with the Integrative Laboratory of Biomechanics and Physiology of Effort, part of the medical school at the University of the Andes in Chile, noted that the effects of air pollutants on animal and human health have been widely described.
In contrast, the effects on physical performance are poorly understood, largely because of the difficulty of implementing an experimental model to study the issue.
Araneda observed that Thoroughbred horse racing involves many animal athletes, of similar genetics, environmental exposure, training, and diet, who participate by breathing varying mixtures of ambient air.
He proposes an analysis strategy based on the common elements of races to determine the effects of pollutants on performance.
Araneda, with a special interest in oxidative damage and lung inflammation in humans arising from exercise in different environmental conditions, carried out a preliminary analysis indicating that air pollutants do indeed affect racehorse performance.
He found that performance is decreased by concentrations of inhalable particles with diameters that are generally 10 micrometers and smaller (PM10), fine inhalable particles, with diameters that are generally 2.5 micrometers and smaller (PM2.5), nitrogen dioxide, nitric oxide and carbon monoxide in the air.
The preliminary findings were based on an examination of 441 official races over distances of 1000m to 1200m at a racecourse in Santiago, Chile, during the summer and winter months of 2012.
The average concentration of pollutants during the six hours before the races were used in the analysis. Readings were obtained just 470m from the course at a station that forms part of the air quality monitoring network in Santiago.
Twenty-seven of the races were discarded from the final analysis because of heavier underfoot track conditions.
Santiago, he noted, has high general levels of pollution, and the racetrack at the center of the study is 800m from a large and busy interprovincial highway.
Araneda said the decreased level of performance observed during high concentrations of pollutants is associated with the fact that exercise causes ventilation to increase.
This phenomenon in humans is associated with an increase in the deposition of particulate material in the lungs, with lung inflammation and oxidative damage resulting.
He noted that, in a 2018 study, researchers found a high percentage of inflammatory patterns, compatible with moderate asthma, in 64 racehorses when analyzing lung lavage fluid. This was associated with increased exposure to particulate matter below 4 micrometers, as well as lower performance of the animals.
The phenomena, he said, may affect the level of performance by limiting oxygen intake, increasing the work of breathing, and may eventually affect the exchange of oxygen and carbon dioxide at tissue level.
From the cardiovascular point of view, during exercise, particulate matter has been associated with increased vascular reactivity, due to increased sympathetic activity.
Araneda said Thoroughbred racehorses are a highly selected and trained group that competes in many parts of the world in diverse environmental conditions.
Racing would appear to provide an opportunity to advance our understanding of the effect of air pollution on physical performance.
It is possible, he said, that there are types of races that would be a good model for study. “According to our results, we believe that horse racing (less than 1200m) in the ‘Handicap’ category can constitute a good group to study the relationship between pollutants and performance.”
Araneda, O.F. Horse Racing as a Model to Study the Relationship between Air Pollutants and Physical Performance. Animals 2022, 12, 1139. doi.org/10.3390/ani12091139