Development of a perceived exertion scale for dogs using selected physiologic parameters

Objective: To develop a perceived exertion scale for dogs exercising on a treadmill and to assess intra- and inter-observer variability. Materials and Methods: Fifteen healthy client-owned dogs participated in paired exercise trials. Measurements of lactate, glucose, heart rate, temperature, respiratory rate and regional tissue oximetry were obtained before, during and after exercise. Perceived exertion scale scores were recorded during exercise and using video recordings to evaluate inter-observer variability. Correlations were evaluated using the Spearman's non-parametric method. Results: Thirteen dogs completed both trials. Dogs walked or trotted on the treadmill with an average perceived exertion score of 2 in both trials. Holter heart rate was positively correlated with perceived exertion scale scores from all observers for both trials. In trial 1, plasma glucose decreased in association with increase in perceived exertion and, in trial 2, cutaneous oximetry decreased, respiratory rate increased and temperature increased with increases on the perceived exertion scale. Inter-observer perceived exertion scale scores were positively correlated in both trials. There was no intra-observer variability between trials. Clinical Significance: The perceived exertion scale correlated with the measured physiologic parameters in dogs exercising at mild to moderate intensity. The perceived exertion scale was consistent and repeatable but larger study numbers and further validation are needed before it can be widely applied.