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Higher skeletal muscular metabolic reserve capacity in COPD patients than healthy subjects
Author(s) -
Rud B.,
Christensen C. C.,
Ryg M.,
Edvardsen A.,
Skumlien S.,
Hallén J.
Publication year - 2009
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/j.1600-0838.2008.00846.x
Subject(s) - copd , medicine , cardiology , skeletal muscle , heart rate , cardiorespiratory fitness , hemoglobin , vo2 max , oxygen saturation , physical therapy , blood pressure , oxygen , chemistry , organic chemistry
We investigated the interaction between skeletal muscle exercise capacity and central restrictions using exercise modalities, which recruit differing levels of muscle mass in eight patients chronic obstructive lung disease (COPD) (FEV 1 % of predicted; 35 [SE 4%]) and eight healthy controls. Subjects performed conventional bicycling, two‐leg knee extensor (2‐KE) and single‐leg knee extensor (1‐KE) exercises. Maximal values for pulmonary V̇ O 2 (VO 2max ), power output, blood lactate, heart rate, blood pressure, and arterial oxygen saturation of hemoglobin were registered. VO 2max in controls was 2453 (210), 1468 (124), and 976 (76) mL/min during bicycling, 2‐KE and 1‐KE, respectively. The COPD patients achieved 48% ( P <0.05), 62% ( P <0.05), and 81% ( P =0.10) of the control values. The mass‐specific VO 2max (VO 2max /exercising muscle mass) during 1‐KE was 345 (25) and 263 (30) mL/kg/min ( P <0.05) in controls and COPD patients, respectively. During 2‐KE the controls and COPD patients achieved 85% (4%) and 67% (5%) ( P =0.06) of the mass‐specific V̇ O 2 during 1‐KE, while during bicycling they achieved 31% (2%) and 17% (1%) ( P <0.05), respectively. The COPD patients have central restrictions when exercising with a relatively small muscle mass (2‐KE) and have a higher muscular metabolic reserve capacity than controls during whole body exercise.