The prevalence of abnormal breathing patterns during exercise and associations with dynamic upper respiratory tract obstructions.

Abstract

REASONS FOR PERFORMING STUDY: There is very limited published information on the prevalence and significance of abnormal breathing patterns adopted during canter/gallop. OBJECTIVES: The aim of this study was to report the prevalence of abnormal breathing patterns during canter/gallop and to investigate whether these may be associated with dynamic upper respiratory tract (URT) obstructions. STUDY DESIGN: Retrospective analysis of clinical records. METHODS: Simultaneous audio and URT videoendoscopy recordings from 365 horses referred for treadmill evaluation were analysed. RESULTS: Thirty percent of horses had an abnormal breathing pattern at canter or gallop, of which 23% had a 2:1 breathing pattern (i.e. one breath is taken over two strides). The prevalence of abnormal breathing patterns was higher at low canter speeds than during strenuous exercise. There was a significant association between breathing pattern during strenuous exercise and the presence of an URT obstruction. CONCLUSIONS: This study suggests that abnormal breathing patterns during canter and gallop may be associated with dynamic URT obstructions; therefore, horses identified by owners or veterinary surgeons to have an abnormal breathing pattern during exercise, in particular a 2:1 breathing pattern, may warrant investigations for diagnosis of respiratory tract disease.