Measurements of blood lactate concentrations are usual in exercise and clinical settings, as they can reveal information about the participant’s fitness. The measurement of blood lactate has long been used as marker of exercise intensity and training status. The purpose of this study was to compare a commercially available lactate oxidase spectrophotometric method (LO) to determine blood lactate levels to two previously validated methods, the lactate dehydrogenase spectrophotometric method (LDH), and the YSI 1500L Sport lactate analyzer (YSI), for possible error or bias, and to identify any potential differences between them.

Blood samples (n = 189) were collected from college-age recreational athletes (n = 11) who were determined to be free of injury. The participants attended five exercise sessions on separate days where, following appropriate warm-up of self-selecting intensity and duration, they rode a cycle ergometer at prescribed and often overlapping intensities.

Capillary blood samples (n = 189) were collected from the earlobe and the blood lactate concentration was determined using each of the three methods. Differences in blood lactate concentrations between the three methods were analyzed using ANOVA (a=0.05).

Although all three experimental protocols yielded similarly shaped lactate curves, the actual values for the LDH method was significantly lower than the HPO and the YSI at every intensity level (bias p<0.05). We conclude that the HPO method is a reliable and valid method to determine blood lactate concentrations spectrophotometrically.

All three methods can provide useful within-subject lactate curves, although we caution against interchangeable use of the three methods.

This article was written in English by Rachel White, Daniel Yaeger y Stasinos Stavrianeas, and published in International Journal of Exercise Science, Volume 2, Issue 2,  p.83-93, 2009

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