Influence of Gender and Racing Performance on Heart Rates during Submaximal Exercise in Thoroughbred Racehorses

We investigated whether gender and racing performance of Thoroughbred racehorses affected the relationship between the heart rate and running speed. Twenty well-trained Thoroughbred racehorses, 7 “open” horses (3 males and 4 females) and 13 “non-open” horses (3 males and 10 females), in JRA Ritto Training Center were used in this study. When the horses cantered around the 500 m circular dirt course at submaximal speed, lap times were measured to calculate mean running speed. Heart rates of the horses were recorded on heart rate monitors during exercise. There was a significant difference in the heart rates between male and female horses (p