科研之友
微信
新浪微博
Facebook
分享链接
摘要
In obesity, an increased work of breathing contributes to a higher O-2 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-O-2 breathing reduces the O-2 cost of cycling and perceived exertion. Nine males [age 16.8 +/- A 1.6 (x +/- A SD) years, body mass 109.9 +/- A 15.0 kg] performed on a cycle ergometer, breathing room air (AIR) or a 21 % O-2-79 % helium mixture (He-O-2): an incremental exercise, for determination of O-2 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. O-2 peak was not different in the two conditions. From the 3rd to the 12th minute of exercise (both during CWR < GET and CWR > GET), O-2 was lower in He-O-2 vs. AIR (end-exercise values: 1.40 +/- A 0.14 vs. 1.57 +/- A 0.22 L min(-1) < GET, and 2.23 +/- A 0.31 vs. 2.54 +/- A 0.27 L min(-1) > GET). During CWR > GET in AIR, O-2 linearly increased from the 3rd to the 12th minute of exercise, whereas no substantial increase was observed in He-O-2. The O-2 cost of cycling was similar to 10 % (< GET) and similar to 15 % (> GET) lower in He-O-2 vs. AIR. Heart rate and ratings of perceived exertion for dyspnea/respiratory discomfort and leg effort were lower in He-O-2. In obese adolescents, acute respiratory muscle unloading via He-O-2 breathing lowered the O-2 cost of cycling and perceived exertion during submaximal moderate- and heavy-intensity exercise.
- 出版日期2015-1
