Is ventilation during maximal exercise limited by dynamic airway closure?

The study is focused on determining if hyperventilation in running horses is due to the limitation of expiratory flow resulting from dynamic airway closure.

Objective of the Research

• The main aim of the research is to investigate whether the phenomena of hypoventilation, observed in horses engaged in maximal exercise such as running, is due to what is known as dynamic airway closure. This condition is characterized by a limitation in the flow of air out of the lungs during expiration.

Research Methodology

• To prove this, the researchers took measurements of peak expiratory flows in a Thoroughbred horse while it was galloping on a treadmill and showing signs of hypoventilation. These results were then compared to the peak flow that the same horse could achieve when undergoing a forced expiratory flow-volume manoeuvre.

Results

• The results indicated that at the rough lung volumes at which the horse was ventilating while running, it didn’t seem to be facing mechanical limitation. This suggested that the horse could potentially increase its expiratory flow, implying that there was reserve capacity available.

Conclusion

• The study concluded that the hypoventilation observed in horses during high-intensity exercise does not appear to be a result of dynamic airway closure.

Implication of the Study

• This research can influence future understanding of respiratory limitations in sport horses during performing strenuous exercises. This could lead to better training protocols or strategies for equine athletes, ensuring their health and performance are optimized.