Climate and Pollution: New Risks to Equine Health

The athletic horse, a true environmental sentinel, now finds itself on the front lines of climate change. A review published in 2025 in *Pferdeheilkunde Equine Medicine* shows that the combination of higher temperatures, increased climate variability, and deteriorating air quality is profoundly altering the health risks to which horses are exposed, both in Europe and elsewhere. Long considered isolated risk factors, these environmental factors are now becoming long-term issues. They affect not only the horse’s respiratory and metabolic health but also its ability to work, recover, and age under good conditions.  

Heat Stress and Air Quality: Interrelated Risks

Rising temperatures are the primary factor contributing to vulnerability. When heat and humidity combine, a horse’s thermoregulatory mechanisms—which rely primarily on sweating—quickly reach their limits. Heat stress results in dehydration, electrolyte imbalances, reduced endurance, and an increase in heatstroke, particularly among older horses, young animals, and horses subjected to intense exertion. In the longer term, these repeated episodes weaken the immune system and prolong recovery times. Climate change also has an indirect but decisive impact. Prolonged droughts and episodes of heavy rain degrade the quality of grazing and forage, increasing the incidence of digestive and metabolic disorders. Above all, warming expands the range and active season of vectors (mosquitoes, ticks, midges), exposing horses to diseases such as West Nile fever (as far north as the United Kingdom) or, more sporadically, African horse sickness.  

Air Pollution and Respiratory Diseases: An Underestimated Link

Added to these pressures is a factor that has long been overlooked: air quality. A horse’s lungs, which are adapted for very high gas exchange during exertion, are particularly vulnerable to fine particulate matter, ozone, nitrogen oxides, and smoke from wildfires. Chronic exposure promotes inflammation of the respiratory tract, equine asthma, and a measurable decline in performance, even in well-trained animals. Smoke from wildfires, which are now more frequent, poses an acute risk. Even at a distance from fire zones, poor air quality can be enough to trigger respiratory problems, particularly in poorly ventilated stables. The authors emphasize that these factors do not simply add up; they reinforce one another. Heat increases the toxicity of certain pollutants, drought increases dust levels, and confinement exacerbates exposure.   The article advocates for structural adaptations, including improved ventilation and shading, real-time environmental monitoring, adjustments to work schedules, and proactive health planning. As the climate becomes increasingly unstable, horses are increasingly seen as an early indicator of environmental effects on animal health and, beyond that, on the relationship between human activities and the well-being of living organisms.