Acute, Low-dose CO Inhalation does not Alter Energy Expenditure during Submaximal Exercise.
Carbon monoxide, a gas known most widely for its toxic effects at high doses, is receiving increased attention for its role as a physiological signaling molecule and potential therapeutic agent when administered in low doses. We sought to quantify any changes to oxygen consumption and energy expenditure during submaximal exercise after low-dose CO inhalation. 9 active individuals completed 4 graded submaximal exercise tests, with each test occurring during a separate visit. For their first exercise test, subjects inhaled CO or room air (1.2 mL·kg(-1) body mass) in a randomized, subject-blind fashion. A second test was repeated 24 h later when the inhaled gas should have cleared the system. Subjects repeated study procedures with the alternate dose after a washout period of at least 2 days. Low-dose CO administration did not affect oxygen consumption or energy expenditure during submaximal exercise immediately or 24 h following its administration. Increases in heart rate, blood [lactate], and perceived exertion were observed following acute CO inhalation but these effects were absent after 24 h. The results of this study suggest that low-dose CO administration does not influence the energetics of submaximal exercise, but it acutely increases the relative intensity associated with absolute workloads below the lactate threshold.
Department of Integrative Physiology, University of Colorado Boulder, Boulder, United States.
L A
LA
Kane
Department of Integrative Physiology, University of Colorado Boulder, Boulder, United States.
B J
BJ
Ryan
Sports Medicine/Sports Physiology, University of Bayreuth, Bayreuth, Germany.
W
W
Schmidt
Department of Integrative Physiology, University of Colorado Boulder, Boulder, United States.
W C
WC
Byrnes
D000280:Administration, Inhalation; D000328:Adult; D002248:Carbon Monoxide / Q000008:administration & dosage* / Q000097:blood; D002263:Carboxyhemoglobin / Q000378:metabolism; D004734:Energy Metabolism / Q000187:drug effects / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006339:Heart Rate; D006452:Hemoglobinometry; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology*; D010465:Perception / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology; D016037:Single-Blind Method
D002248:Carbon Monoxide; D002263:Carboxyhemoglobin