Heart rates and blood lactate response in thoroughbred horses during a race

Abstract

We measured the heart rate before, during and after a 1200-m race, and blood lactate concentration at 10 min after a race in 23 Thoroughbred horses. The heart rate increased when horses were walking through the underground passage and after the jockeys mounted them in the paddock, even though there was no increase in exercise intensity. During the canter from the exit of the underground passage to the starting stalls, the heart rate increased to a peak value of 194.0 ± 2.0 (mean ± SE) beat/min, which was equivalent to 91.1 ± 0.8% of the maximal racing heart rate. In the starting stalls immediately before the start of the race, the heart rate was 171.4 ± 5.3 beat/min. The peak value of the heart rate (HRpeak) during the race was 213.6 ± 1.7 beat/min, and the time taken to reach 95% of HR peak was 12.4 ± 1.8 sec. The blood lactate concentration after the race was 22.5 ± 0.6 mmol/l. The mean speed of the horses was 15.9 ± 0.0 m/s, which was similar to those of 3-year-olds in maiden races. These data could be useful for planning training strategies for Thoroughbred horses.