Researchers at Oklahoma State University (OSU) recently completed a study on airway cooling and mucosal injury during cold weather exercise. Using the Thoroughbred racehorse as a model, scientists found that even cantering in sub-freezing temperatures can induce airway obstruction (bronchoconstriction, or airway contraction). The research appeared in the February issue of the Journal of Applied Physiology.

Human subjects that routinely perform strenuous exercise in cold conditions have a higher prevalence of chronic airway inflammation and hyperactivity (often referred to as “ski asthma” because its effects are often found in cross-country skiers). The scientists set out to determine whether exercise while breathing cold air could cause chronic airway disease in the equine athlete.

Previous studies in both humans and horses have confirmed that when exercising in subfreezing temperatures with low humidity, the upper airways fail to fully warm the inhaled air, leading to considerable loss of heat and water from the lower airways. These studies also confirmed that this stimulus is associated with airway mucosal damage.

“Our data show that exercising in cold air can provoke airway changes in otherwise healthy horses and may in fact be a part of the cause of the eventual development of chronic airway disease in equine athletes,” explained lead researcher Michael S. Davis, DVM, MS, PhD, Dipl. ACVIM