The effect of pre-test carbohydrate ingestion on the anaerobic threshold, as determined by the lactate-minimum test

Appl Physiol Nutr Metab. 2007 Dec;32(6):1058-64. doi: 10.1139/H07-066.

Abstract

The purpose of this study was to investigate the effect of pre-test carbohydrate (CHO) ingestion on anaerobic-threshold assessment using the lactate-minimum test (LMT). Fifteen competitive male distance runners capable of running 10 km in 33.5-43 min were used as subjects. LMT was performed following CHO (2x300 mL, 7% solution) or comparable placebo (Pl) ingestion, in a double-blind, randomized order. The LMT consisted of two high-intensity 1 min treadmill runs (17-21 km.h(-1)), followed by an 8 min recovery period. Subsequently, subjects performed 5 min running stages, incremented by 0.6 km.h(-1) and separated by 1 min blood-sampling intervals. Tests were terminated after 3 consecutive increases in blood-lactate concentration ([La]) had been observed. Finger-tip capillary blood was sampled for [La] and blood-glucose determination 30 min before the test's onset, during the recovery phase following the 2 high-intensity runs, and following each of the subsequent 5 min stages. Heart rate (HR) and rating of perceived exertion (RPE) were recorded after each stage. The lactate-minimum speed (LMS) was determined from the individual [La]-velocity plots and was considered reflective of the anaerobic threshold. Pre-test CHO ingestion had no effect on LMS (13.19+/-1.12 km.h(-1) vs. 13.17+/-1.08 km.h(-1) in CHO and Pl, respectively), nor on [La] and glucose concentration at that speed, or on HR and RPE responses. Pre-test CHO ingestion therefore does not affect LMS or the LMT-estimated anaerobic threshold.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Anaerobic Threshold / drug effects*
  • Anthropometry
  • Blood Glucose / metabolism
  • Carbohydrates / pharmacology*
  • Double-Blind Method
  • Humans
  • Lactic Acid / blood*
  • Male
  • Oxygen Consumption / drug effects
  • Running / physiology

Substances

  • Blood Glucose
  • Carbohydrates
  • Lactic Acid