Study: Lactate Levels Could Guide Equine Conditioning Programs

Low-intensity exercise over long periods was an effective approach to conditioning horses, as indicated by blood lactate levels measured in a new study.

Blood lactate, the ionized form of lactic acid, which is a byproduct of anaerobic metabolism, can provide an indication of a horse's fitness, but there was previously little information about whether these levels could be used to determine the speed of exercise to improve overall fitness.

The researchers measured the speed at which blood lactate concentration reached 4 mmol/L (v4), the level considered optimum for a horse's fitness conditioning, via several different training regimens.

"High v4 values have a high relationship with competitive success for horses competing in many sport disciplines," said study co-author Arno Lindner, DVM, PhD, of the Arbeitsgruppe Pferd in Jülich, Germany.

Researchers examined the effect of three different treadmill exercise programs on six 2-year-old Haflinger stallions. They determined the individual speeds by testing the animals to see when blood lactate concentrations reached 4 mmol/L, 1.5 mmol/L (v1.5) and 2.5 mmol/L (v2.5). The v4 conditioning program lasted 25 minutes and the other two programs lasted 45 minutes. All tests were performed on a 17% incline.

Each program consisted of exercise every other day for six weeks. Horses had a five week rest period before switching to the next conditioning program. All horses participated in all three programs, after which the researchers compared the programs' effect on the horses' fitness.

While the researchers did not find a significant difference among the three programs, Lindner noted this could be due to the fact that the handlers did not increase the intensity of the exercise as horses became more conditioned. However, the results did favor longer exercises done at a lower speed as opposed to shorter, faster exercise.

Lindner added that there are objective criteria to guide the intensity of exercise for each individual, and trainers might consider this testing to evaluate the horse's fitness.

The study, "Effect of blood lactate-guided conditioning of horses with exercises of differing durations and intensities on heart rate and biochemical blood variables," was published in October in the Journal of Animal Science. The abstract is available on PubMed.

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