Salvadego Desy, Sartorio Alessandro, Agosti Fiorenza, Tringali Gabriella, Patrizi Alessandra, Mauro Antonella Lo, Aliverti Andrea, Grassi Bruno
Department of Medical and Biological Sciences, University of Udine, Piazzale M. Kolbe 4, 33100, Udine, Italy.
Eur J Appl Physiol. 2015 Jan;115(1):99-109. doi: 10.1007/s00421-014-2993-8. Epub 2014 Sep 12.
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.
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.
[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.
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.
在肥胖状态下，呼吸功增加会导致运动时的氧气消耗增加，并对运动耐力产生负面影响。本研究的目的是确定在肥胖青少年中，通过常氧氦氧混合气呼吸实现急性呼吸肌负荷减轻是否能降低骑自行车时的氧气消耗和主观用力感觉。
9名男性[年龄16.8±1.6（x±标准差）岁，体重109.9±15.0千克]在自行车测力计上进行运动，呼吸室内空气（AIR）或21%氧气-79%氦气混合气（He-O2）：进行递增运动，以测定[公式：见正文]峰值摄氧量和气体交换阈值（GET）；在AIR中测定的GET的70%（<GET）和120%（>GET）下进行12分钟的恒定工作率（CWR）运动。
两种条件下的[公式：见正文]峰值摄氧量无差异。在运动的第3分钟至第12分钟（CWR<GET和CWR>GET期间），He-O2组的[公式：见正文]摄氧量低于AIR组（运动结束时的值：<GET时为1.40±0.14对1.57±0.22升/分钟，>GET时为2.23±0.31对2.54±0.27升/分钟）。在AIR中CWR>GET期间，[公式：见正文]摄氧量在运动的第3分钟至第12分钟呈线性增加，而在He-O2组中未观察到显著增加。与AIR相比，He-O2组骑自行车的氧气消耗在<GET时低约10%，在>GET时低约15%。He-O2组的心率以及呼吸困难/呼吸不适和腿部用力的主观用力感觉评分较低。
在肥胖青少年中，通过He-O2呼吸实现急性呼吸肌负荷减轻可降低次最大强度中、高强度运动时骑自行车的氧气消耗和主观用力感觉。
