Blood Lactate as a Metabolic Biomarker of Anaerobic Vocal Capacity: A Pilot Study.

Purpose: Blood lactate concentration is commonly used to assess metabolic demand and skeletal muscle training response. The objective of the pilot study was to investigate if a change in blood lactate was detectable in an anaerobically designed vocal demand task vocal capacity anaerobic task (VCAT) and determine if the developed vocal demand task may assess the anaerobic capacity of the voice musculature, like anaerobic power tests commonly used in applied exercise science.

Methods: A prospective repeated measures study quantified blood lactate concentration preVCAT and postVCAT in vocally healthy adults. The secondary outcomes included determining correlations and predictors of the change in lactate including aerodynamic, leg anaerobic capacity and anthropometric measures as well as participant reported vocal fatigue.

Results: A significant positive change in lactate pre and post VCAT was observed (P = 0.003). Regression analyses showed that Body mass index (P = 0.003) was a predictor of the lactate concentration shift. There was no evidence of additional measured variables or their interactions being predictors of the blood lactate concentration levels detected via the vocal demand task.

Conclusions: Evidence supports the hypothesis that blood lactate may be an effective metabolic biomarker in investigating voice physiology in vivo. The VCAT, via the shift in systemic blood lactate concentration, may provide a means from which to understand metabolic adaptations that occur in the peripheral muscles of the voice mechanism during behavioral voice intervention. Further investigations are needed to determine the clinical significance of the measured blood lactate as well as to refine the proposed anaerobic vocal demand task.