Acute respiratory muscle unloading by normoxic helium–O2 breathing reduces the O2 cost of cycling and perceived exertion in obese adolescents

Desy Salvadego, Alessandro Sartorio, Fiorenza Agosti, Gabriella Tringali, Alessandra Patrizi, Antonella Lo Mauro, Andrea Aliverti, Bruno Grassi

Research output: Contribution to journalArticle

Abstract

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 $$ \mathop V\limits^{.} $$V.O2 peak and gas exchange threshold (GET); 12 min constant work rate (CWR) exercises at 70 % of GET (GET) determined in AIR. Results: $$ \mathop V\limits^{.} $$V.O2 peak was not different in the two conditions. From the 3rd to the 12th minute of exercise (both during CWR  GET), $$ \mathop V\limits^{.} $$V.O2 was lower in He–O2 vs. AIR (end-exercise values: 1.40 ± 0.14 vs. 1.57 ± 0.22 L min−1 −1 >GET). During CWR > GET in AIR, $$ \mathop V\limits^{.} $$V.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) 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.

Original languageEnglish
Pages (from-to)99-109
Number of pages11
JournalEuropean Journal of Applied Physiology
Volume115
Issue number1
DOIs
Publication statusPublished - Jan 17 2015

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Keywords

  • Exercise tolerance
  • Helium–O<inf>2</inf> breathing
  • O<inf>2</inf> cost of exercise
  • Obesity
  • Respiratory muscles

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health
  • Orthopedics and Sports Medicine
  • Physiology (medical)
  • Medicine(all)

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