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