ORIGINAL ARTICLES   

The Journal of Sports Medicine and Physical Fitness 1998 September;38(3):240-4

Copyright © 1999 EDIZIONI MINERVA MEDICA

language: English

Acute L-glutamine ingestion does not improve maximal effort exercise

Haub M. D. ¹, Potteiger J. A. ¹, Nau K. l: ², Webster M. J. ³, Zebas C. J. ¹

¹ Exercise Physiology Laboratory, University of Kansas Medical Center; ² Department of Physical Therapy Education, University of Kansas Medical Center; ³ Laboratory of Applied Physiology, University of Southern Mississippi, USA

Background. L-glu­ta­mine (GLN) may ­have an ergo­gen­ic ­effect dur­ing exer­cise con­sid­er­ing its ­base gen­er­at­ing poten­tial. We attempt­ed to deter­mine wheth­er GLN inges­tion influ­enc­es ­acid-­base bal­ance and ­improves ­high inten­sity exer­cise per­for­mance.
Method. Ten ­trained ­males per­formed ­five exer­cise ­bouts on a ­cycle ergom­e­ter at l00% of V.O2­peak. The ­first ­four ­bouts ­were 60 sec in dura­tion, ­while the ­fifth ­bout was con­tin­ued to ­fatigue. Each ­bout was sep­ar­at­ed by 60 sec of recov­ery. The exer­cise ­bouts ­were initiat­ed 90 min ­after ingest­ing 0.03 g·kg ­body ­mass-1 of ­either GLN or pla­ce­bo (PLC). Venous ­blood sam­ples ­were col­lect­ed pre-inges­tion (PRE-IN), pre-exer­cise (PRE-EX), and fol­low­ing ­bouts ­four (B4) and ­five (B5) and ana­lyzed for pH, bicar­bo­nate con­cen­tra­tion (HCO3), and lac­tate con­cen­tra­tion (La-). Time to ­fatigue for B5 was ­used as a per­for­mance meas­ure.
Results. pH, [HCO3], and [La-] ­were not sig­nif­i­cant­ly dif­fer­ent (p>0.05) ­between con­di­tions for PRE-IN, PRE-EX, B4, and B5. Time to ­fatigue was not sig­nif­i­cant­ly dif­fer­ent ­between con­di­tions and aver­aged 263.4±24.5 sec and 263.2±19.4 sec for the GLN and PLC ­trials, respec­tive­ly.
Conclusions. These ­data indi­cate ­that ­acute inges­tion of L-glu­ta­mine ­does not ­enhance ­either buf­fer­ing poten­tial or ­high inten­sity exer­cise per­for­mance in ­trained ­males.