Exercise Tests in Saddle Horses, 2: The Kinetics of Blood Lactate During Constant Exercise Tests on a Treadmill

Abstract Kinetics of blood lactate was followed in five three-day-event horses. Two tests were made at constant velocity during 8 min on a treadmill, first at VLa 3 then at VLa 4 . These velocities were determined for each horse by an exercise step test in a previous study. In constant velocity tests, a rapid rise in blood lactate was observed up until the third minute of exercise. For the VLaa test, a steady state was achieved between the 4th and the 8th rain. Horses completed the test with a blood lactate concentration lower than 3 mmol/1. The anaerobic threshold could be estimated at 2.25 ± 0.40 mmol/1. For the VLa4 test blood lactate rose linearly from the let to the 8th rain and no steady state was achieved. The mean rate of accumulation was 0.25 mmol/1/min. For three-day-event horses, VLa 4 did not represent the individual anaerobic threshold for an 8 min constant exercise.