Ventilatory and gas-exchange responses to incremental exercise performed with reduced muscle glycogen content

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Title Ventilatory and gas-exchange responses to incremental exercise performed with reduced muscle glycogen content
Author Sabapathy, Surendran; Morris, Norman; Schneider, Donald Anthony
Journal Name Journal of Science and Medicine in Sport
Editor Caroline Finch
Year Published 2006
Place of publication Australia
Publisher Elsevier
Abstract This study examined the relationship between minute ventilation (VE), CO2 production (VCO2), and blood lactate concentration ([La−]) during incremental exercise performed with reduced muscle glycogen stores. Nine untrained female subjects (25.3 ± 4.2 year) performed incremental cycling in a normal glycogen (NG) state and under conditions of reduced muscle glycogen (RG) content. To reduce muscle glycogen stores, subjects cycled to exhaustion (124 ± 33 min) at a power output corresponding to their gas-exchange anaerobic threshold. Peak oxygen uptake (VO2peak) was unchanged with glycogen reduction, even though subjects achieved a significantly lower maximal power output in the RG state (p < 0.05). Peak blood [La−] decreased significantly by 37% in the RG state (p < 0.001). At any percentage of VO2peak, O2 uptake and VE were similar for both treatment conditions, whereas VCO2 and respiratory exchange ratio values were lower during the RG trial than under NG conditions. Therefore, VE/VCO2 tended to be higher and end-tidal CO2 partial pressure tended to be lower during exercise performed in the RG state. VE was significantly correlated with VCO2 under both treatment conditions (NG: r = 0.99, p < 0.01; RG: r = 0.99, p < 0.01). However, the slope of the VE-VCO2 relationship was significantly elevated during the RG trial (p < 0.01). VE during exercise was similar under both treatment conditions, even though VCO2 and blood [La−] were lower during the RG trial compared to the NG trial. This suggests that factors other than CO2 delivery to the lung and metabolic acidosis play an important role in regulating during exercise.
Peer Reviewed Yes
Published Yes
Publisher URI http://elsevier.com/locate/jsams
Alternative URI http://dx.doi.org/10.1016/j.jsams.2006.03.024
Volume 9
Issue Number 3
Page from 267
Page to 273
ISSN 1440-2440
Date Accessioned 2006-06-08
Language en_AU
Research Centre Heart Foundation Research Centre; Griffith Health Institute
Faculty Griffith Health Faculty
Subject PRE2009-Exercise Physiology
URI http://hdl.handle.net/10072/14282
Publication Type Journal Articles (Refereed Article)
Publication Type Code c1

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