The effects of intensity and duration of training on blood lactate concentrations during and after exercise

Summary The effects of training intensity and duration on blood lactate concentrations during submaximal and after maximal treadmill exercise were investigated in 2 groups of 5 Thoroughbred horses. Horses were trained on a treadmill in either a ‘fast’ or ‘slow’ group. In the ‘fast’ group, all exercise after an initial warm‐up was at speeds which resulted in blood lactate concentrations in the range 4–8 mmol/l. In the ‘slow’ group, all training exercise was at half the speed but equal distance. Incremental speed treadmill tests were repeated after 1, 2, 3, 5, 7 and 9 weeks training. Treadmill speeds and oxygen uptake at blood lactate of 4 mmol/l (V La4 and V̇O 2 ‐4) and blood lactate concentration at 9 m/s (La 9 ) were measured. Blood was also collected at 2 or 5 min intervals after a run to fatigue at 115% of maximum oxygen uptake (V̇O 2max ). Peak and 10 min post exercise lactate concentrations were measured, and disappearance rate (mmol/l/min) calculated. Runs to fatigue were repeated after 5 and 9 weeks of training. Data were analysed by repeated measures ANCOVA. Mean ± s.e.m. V La4 increased from 7.0 ± 0.5 to 9.2 ± 0.2 m/s (P<0.001) and La 9 decreased from 8.0 ± 1.0 to 3.9 ± 0.3 mmol/l (P<0.001) over the 9 weeks training. The pooled V̇O 2 ‐4 increased from mean ± s.e.m. 96 ± 6.6 to 122 ± 5.6 ml/min/kg (P<0.01) after training. An increase in the pooled %V̇O 2max ‐4 from 79 ± 3.4% to 84 ± 2.4% after 9 weeks training was not statistically significant. There were no significant effects of training intensity on changes in V La4 , La 9 , or V̇O 2 ‐4 and no significant effects of training on lactate concentrations after exercise to fatigue at 115% V̇O 2max . The training induced decrease in blood lactate concentration during submaximal exercise is not dependent on intensity of exercise during training.