Physiological correlates of endurance time variability during constant-workrate cycling exercise in patients with COPD.
RATIONALE: The endurance time (T(end)) during constant-workrate cycling exercise (CET) is highly variable in COPD. We investigated pulmonary and physiological variables that may contribute to these variations in T(end). METHODS: Ninety-two patients with COPD completed a CET performed at 80% of peak...
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2011-01-01
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| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC3046138?pdf=render |
| _version_ | 1818109586564972544 |
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| author | Isabelle Vivodtzev Philippe Gagnon Véronique Pepin Didier Saey Louis Laviolette Cynthia Brouillard François Maltais |
| author_facet | Isabelle Vivodtzev Philippe Gagnon Véronique Pepin Didier Saey Louis Laviolette Cynthia Brouillard François Maltais |
| author_sort | Isabelle Vivodtzev |
| collection | DOAJ |
| description | RATIONALE: The endurance time (T(end)) during constant-workrate cycling exercise (CET) is highly variable in COPD. We investigated pulmonary and physiological variables that may contribute to these variations in T(end). METHODS: Ninety-two patients with COPD completed a CET performed at 80% of peak workrate capacity (W(peak)). Patients were divided into tertiles of T(end) [Group 1: <4 min; Group 2: 4-6 min; Group 3: >6 min]. Disease severity (FEV(1)), aerobic fitness (W(peak), peak oxygen consumption [VO2(peak)], ventilatory threshold [VO2(VT)]), quadriceps strength (MVC), symptom scores at the end of CET and exercise intensity during CET (heart rate at the end of CET to heart rate at peak incremental exercise ratio [HR(CET)/HR(peak)]) were analyzed as potential variables influencing T(end). RESULTS: W(peak), VO2(peak), VO2(VT), MVC, leg fatigue at end of CET, and HR(CET)/HR(peak) were lower in group 1 than in group 2 or 3 (p≤0.05). VO2(VT) and leg fatigue at end of CET independently predicted T(end) in multiple regression analysis (r = 0.50, p = 0.001). CONCLUSION: T(end) was independently related to the aerobic fitness and to tolerance to leg fatigue at the end of exercise. A large fraction of the variability in T(end) was not explained by the physiological parameters assessed in the present study. Individualization of exercise intensity during CET should help in reducing variations in T(end) among patients with COPD. |
| first_indexed | 2024-12-11T02:33:37Z |
| format | Article |
| id | doaj.art-7207d51af2034ef997394fcc3726a386 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-11T02:33:37Z |
| publishDate | 2011-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-7207d51af2034ef997394fcc3726a3862022-12-22T01:23:47ZengPublic Library of Science (PLoS)PLoS ONE1932-62032011-01-0162e1700710.1371/journal.pone.0017007Physiological correlates of endurance time variability during constant-workrate cycling exercise in patients with COPD.Isabelle VivodtzevPhilippe GagnonVéronique PepinDidier SaeyLouis LavioletteCynthia BrouillardFrançois MaltaisRATIONALE: The endurance time (T(end)) during constant-workrate cycling exercise (CET) is highly variable in COPD. We investigated pulmonary and physiological variables that may contribute to these variations in T(end). METHODS: Ninety-two patients with COPD completed a CET performed at 80% of peak workrate capacity (W(peak)). Patients were divided into tertiles of T(end) [Group 1: <4 min; Group 2: 4-6 min; Group 3: >6 min]. Disease severity (FEV(1)), aerobic fitness (W(peak), peak oxygen consumption [VO2(peak)], ventilatory threshold [VO2(VT)]), quadriceps strength (MVC), symptom scores at the end of CET and exercise intensity during CET (heart rate at the end of CET to heart rate at peak incremental exercise ratio [HR(CET)/HR(peak)]) were analyzed as potential variables influencing T(end). RESULTS: W(peak), VO2(peak), VO2(VT), MVC, leg fatigue at end of CET, and HR(CET)/HR(peak) were lower in group 1 than in group 2 or 3 (p≤0.05). VO2(VT) and leg fatigue at end of CET independently predicted T(end) in multiple regression analysis (r = 0.50, p = 0.001). CONCLUSION: T(end) was independently related to the aerobic fitness and to tolerance to leg fatigue at the end of exercise. A large fraction of the variability in T(end) was not explained by the physiological parameters assessed in the present study. Individualization of exercise intensity during CET should help in reducing variations in T(end) among patients with COPD.http://europepmc.org/articles/PMC3046138?pdf=render |
| spellingShingle | Isabelle Vivodtzev Philippe Gagnon Véronique Pepin Didier Saey Louis Laviolette Cynthia Brouillard François Maltais Physiological correlates of endurance time variability during constant-workrate cycling exercise in patients with COPD. PLoS ONE |
| title | Physiological correlates of endurance time variability during constant-workrate cycling exercise in patients with COPD. |
| title_full | Physiological correlates of endurance time variability during constant-workrate cycling exercise in patients with COPD. |
| title_fullStr | Physiological correlates of endurance time variability during constant-workrate cycling exercise in patients with COPD. |
| title_full_unstemmed | Physiological correlates of endurance time variability during constant-workrate cycling exercise in patients with COPD. |
| title_short | Physiological correlates of endurance time variability during constant-workrate cycling exercise in patients with COPD. |
| title_sort | physiological correlates of endurance time variability during constant workrate cycling exercise in patients with copd |
| url | http://europepmc.org/articles/PMC3046138?pdf=render |
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