07/20/2026
๐ซ๏ธ ๐๐จ๐จ๐ซ ๐๐ข๐ซ ๐๐ฎ๐๐ฅ๐ข๐ญ๐ฒ: ๐๐ก๐๐ง ๐๐๐ง ๐๐จ๐ซ๐ฌ๐๐ฌ ๐๐๐ญ๐ฎ๐ซ๐ง ๐ญ๐จ ๐๐จ๐ซ๐ค?๐ด
In the last 20 years, wildfires have become more frequent, more intense, and larger, with the greatest increase in extreme fire behavior observed in the western United States and the northern parts of North America and Russia.
These extreme fire events have contributed to periods of poor air quality that negatively impact the respiratory health of both people and animals.
๐๐ก๐๐ญ ๐๐ซ๐ ๐๐๐.๐ ๐๐ง๐ ๐ฐ๐ก๐ฒ ๐๐ซ๐ ๐ญ๐ก๐๐ฒ ๐ฌ๐จ ๐ก๐๐ซ๐ฆ๐๐ฎ๐ฅ?
These negative impacts are largely attributed to the small particles known as PM2.5 that are present in smoke. PM2.5 are microscopic airborne particles that are about 30 times smaller than the width of the average human hair. This means they can easily sneak past the body's natural defenses.
As they are inhaled, they may cause immediate irritation and inflammation of the airways, resulting in coughing or shortness of breath. However, because these particles are inhaled deep into the lungs, they can pe*****te the alveoli, enter the bloodstream, and impact organs throughout the body. This can damage the lining of blood vessels and lead to systemic inflammation and oxidative stress.
These health effects are most commonly observed when the Air Quality Index (AQI) exceeds 151 on a scale of 0 to 500. However, negative impacts may occur at lower AQI levels in horses with underlying respiratory or cardiovascular conditions.
๐๐จ๐ฐ ๐๐จ๐๐ฌ ๐ฆ๐ฒ ๐ก๐จ๐ซ๐ฌ๐ ๐ซ๐๐๐จ๐ฏ๐๐ซ ๐๐ซ๐จ๐ฆ ๐ฉ๐จ๐จ๐ซ ๐๐ข๐ซ ๐ช๐ฎ๐๐ฅ๐ข๐ญ๐ฒ?
While many horse owners monitor the current AQI and make the necessary adjustments to reduce health risks, they often don't realize that poor air quality can continue to affect the body even after the AQI returns to healthy levels. This is because the body needs time to remove the particles and repair damaged tissues.
The lungs rely on natural clearance mechanisms, including coughing and tiny hair-like structures called cilia, to move particle-filled mucus out of the respiratory tract. For particles that have entered the tissues, specialized white blood cells called macrophages engulf and remove them. Once exposure stops, the body also begins repairing damaged cells and resolving oxidative stress by neutralizing the free radicals responsible for inflammation and tissue damage.
Unfortunately, these processes take time. While the healing process is estimated to take 4 to 6 weeks, the exact timeline depends on several factors:
๐น The extent and duration of exposure. The poorer the air quality and the longer the exposure, the more time a horse will need to recover. For example, an AQI of 400 is expected to cause more damage and require a longer recovery period than an AQI of 150.
๐น Horse management during exposure. Horses may require more time to heal if they continued working or participated in activities during periods of poor air quality. Exercise, hauling, or even running and playing during turnout increases respiratory rate, resulting in greater inhalation of PM2.5 particles and increased overall exposure.
๐น The horse's health before exposure. Horses that are out of shape or have pre-existing respiratory or cardiovascular conditions may require a longer recovery period. Every horse should be evaluated individually when developing a return-to-work plan.
๐๐ก๐๐ง ๐๐๐ง ๐ฆ๐ฒ ๐ก๐จ๐ซ๐ฌ๐ ๐ซ๐๐ฌ๐ฎ๐ฆ๐ ๐ฐ๐จ๐ซ๐ค?
Current recommendations from Oregon State University and UC Davis suggest allowing horses to rest for a minimum of 7 to 14 days under healthy air conditions before returning to work. More conservative recommendations suggest that 4 to 6 weeks is ideal to allow the respiratory tract to heal fully and reduce the risk of re-aggravating the airways.
A "healthy air day" is generally considered a 24-hour period during which the AQI remains below 100.
After the appropriate recovery period, healthy horses should return to work gradually, beginning with hand walking. Throughout the process, monitor your horse closely for signs of respiratory distress, including:
๐ด Coughing
๐ Nasal discharge
๐ฎโ๐จ An elevated respiratory rate
๐ซ Reluctance to work
If any of these signs develop, reduce the workload and consult your veterinarian.
๐๐จ ๐ฐ๐ก๐๐ญ ๐๐จ๐๐ฌ ๐๐ฅ๐ฅ ๐จ๐ ๐ญ๐ก๐ข๐ฌ ๐ฆ๐๐๐ง?
I want to take a moment to emphasize that I am not a veterinarian; rather, I have a Ph.D. in Equine Science. However, here's how I interpret the current recommendations:
When developing a recovery plan, many factors need to be considered. As I dug deeper into the 4- to 6-week recommendation, it appears to have originated from UC Davis during years when California experienced severe and prolonged wildfire smoke exposure. While 4 to 6 weeks may be ideal, UC Davis also acknowledged that many owners of performance horses may wish to return to work sooner, and that horses experiencing only mild smoke exposure may require a shorter recovery period.
Based on those recommendations, a 2- to 4-week recovery period may be reasonable for horses with relatively mild smoke exposure that remain clinically healthy, while 4 to 6 weeks is a more appropriate goal following prolonged or severe exposure.
When returning to work, don't expect your horse to immediately resume its previous workload. Start with hand walking and walking under saddle for at least a week before gradually reintroducing trot and, eventually, canter work.
Finally, remember that every horse is different. What works well for one horse may not be appropriate for another. Fitness level, age, pre-existing health conditions, the severity of smoke exposure, and individual response all play important roles in determining how quickly a horse can safely return to exercise.
๐๐ก๐ ๐๐จ๐ญ๐ญ๐จ๐ฆ ๐๐ข๐ง๐
I know it's frustrating, especially in the middle of competition season, and it may feel like a setback. However, patience is one of the best investments you can make in your horse's long-term respiratory health.
Returning to work too soon can prolong the healing process and potentially worsen existing airway damage. By managing your horse appropriately during periods of poor air quality, allowing adequate recovery time, and gradually returning to work while monitoring for signs of respiratory distress, you'll give your horse the best opportunity for a full recovery.
Cheers,
Dr. DeBoer
