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The effects of creatine loading on oxygen uptake kinetics during heavy exercise
Author(s) -
Butts Cory L,
Adamus Heather,
Keller David M,
McDonough Paul
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.718.1
Subject(s) - phosphocreatine , creatine , kinetics , chemistry , medicine , oxygen , endocrinology , biochemistry , energy metabolism , physics , organic chemistry , quantum mechanics
The kinetics of oxygen uptake during the rest to exercise transition are thought to be modulated by intracellular metabolic processes. Evidence suggests that increased phosphocreatine stores may impact the kinetics of VO 2 , namely, slowing kinetics due to the now increased ATP buffering capacity. Thus, the purpose of this study was to test the hypothesis that creatine loading would induce slowed VO 2 kinetics during heavy leg cycling. Four (N=4) subjects completed three separate exercise bouts of heavy (supra‐lactate threshold) exercise both prior to and following a creatine loading regimen. VO 2 was measured continuously at the mouth during exercise and recovery for each bout. During the on‐transition, the total amplitude was reduced following creatine loading (A tot : Control 1.22±0.26 vs Creatine 0.97±0.20 L/min, p = 0.03). The time constant during the off‐transition was also slower during the creatine trials (Tau: Control 36.4±9.3 vs Creatine 53.3±7.6 sec, p = 0.02). These findings suggest that an increase in the temporal buffering capacity of phosphocreatine reduces the on‐transient VO 2 as well as, slowing the recovery kinetics of VO 2 .