PURPOSE: In obesity, an increased work of breathing contributes to a higher O2 cost of exercise and negatively affects exercise tolerance. The purpose of the study was to determine whether, in obese adolescents, acute respiratory muscle unloading via normoxic helium-O2 breathing reduces the O2 cost of cycling and perceived exertion. METHODS: Nine males [age 16.8 ± 1.6 (x ± SD) years, body mass 109.9 ± 15.0 kg] performed on a cycle ergometer, breathing room air (AIR) or a 21 % O2-79 % helium mixture (He-O2): an incremental exercise, for determination of [Formula: see text]O2 peak and gas exchange threshold (GET); 12 min constant work rate (CWR) exercises at 70 % of GET (<GET) and 120 % of GET (>GET) determined in AIR. RESULTS: [Formula: see text]O2 peak was not different in the two conditions. From the 3rd to the 12th minute of exercise (both during CWR < GET and CWR > GET), [Formula: see text]O2 was lower in He-O2 vs. AIR (end-exercise values: 1.40 ± 0.14 vs. 1.57 ± 0.22 L min(-1) <GET, and 2.23 ± 0.31 vs. 2.54 ± 0.27 L min(-1) >GET). During CWR > GET in AIR, [Formula: see text]O2 linearly increased from the 3rd to the 12th minute of exercise, whereas no substantial increase was observed in He-O2. The O2 cost of cycling was ~10 % (<GET) and ~15 % (>GET) lower in He-O2 vs. AIR. Heart rate and ratings of perceived exertion for dyspnea/respiratory discomfort and leg effort were lower in He-O2. CONCLUSIONS: In obese adolescents, acute respiratory muscle unloading via He-O2 breathing lowered the O2 cost of cycling and perceived exertion during submaximal moderate- and heavy-intensity exercise.
PURPOSE: In obesity, an increased work of breathing contributes to a higher O2 cost of exercise and negatively affects exercise tolerance. The purpose of the study was to determine whether, in obese adolescents, acute respiratory muscle unloading via normoxic helium-O2 breathing reduces the O2 cost of cycling and perceived exertion. METHODS: Nine males [age 16.8 ± 1.6 (x ± SD) years, body mass 109.9 ± 15.0 kg] performed on a cycle ergometer, breathing room air (AIR) or a 21 % O2-79 % helium mixture (He-O2): an incremental exercise, for determination of [Formula: see text]O2 peak and gas exchange threshold (GET); 12 min constant work rate (CWR) exercises at 70 % of GET (<GET) and 120 % of GET (>GET) determined in AIR. RESULTS: [Formula: see text]O2 peak was not different in the two conditions. From the 3rd to the 12th minute of exercise (both during CWR < GET and CWR > GET), [Formula: see text]O2 was lower in He-O2 vs. AIR (end-exercise values: 1.40 ± 0.14 vs. 1.57 ± 0.22 L min(-1) <GET, and 2.23 ± 0.31 vs. 2.54 ± 0.27 L min(-1) >GET). During CWR > GET in AIR, [Formula: see text]O2 linearly increased from the 3rd to the 12th minute of exercise, whereas no substantial increase was observed in He-O2. The O2 cost of cycling was ~10 % (<GET) and ~15 % (>GET) lower in He-O2 vs. AIR. Heart rate and ratings of perceived exertion for dyspnea/respiratory discomfort and leg effort were lower in He-O2. CONCLUSIONS: In obese adolescents, acute respiratory muscle unloading via He-O2 breathing lowered the O2 cost of cycling and perceived exertion during submaximal moderate- and heavy-intensity exercise.
Authors: Gaspar R Chiappa; Fernando Queiroga; Ethiane Meda; Leonardo F Ferreira; Fernando Diefenthaeler; Marcos Nunes; Marco A Vaz; Maria Christina L Machado; Luis Eduardo Nery; J Alberto Neder Journal: Am J Respir Crit Care Med Date: 2009-03-19 Impact factor: 21.405
Authors: Emil S Walsted; Azmy Faisal; Caroline J Jolley; Laura L Swanton; Matthew J Pavitt; Yuan-Ming Luo; Vibeke Backer; Michael I Polkey; James H Hull Journal: J Appl Physiol (1985) Date: 2017-11-02
Authors: Kim D Lu; Krikor Manoukian; Shlomit Radom-Aizik; Dan M Cooper; Stanley P Galant Journal: Pediatr Exerc Sci Date: 2015-11-30 Impact factor: 2.333
Authors: Hailu K Alemayehu; Desy Salvadego; Miriam Isola; Gabriella Tringali; Roberta De Micheli; Mara Caccavale; Alessandro Sartorio; Bruno Grassi Journal: Physiol Rep Date: 2018-10