title: Training improves muscle oxidative capacity and oxygenation recovery kinetics in patients with chronic obstructive pulmonary disease.
abstract: We studied 21 patients with chronic obstructive pulmonary disease aged [mean (SD)] 63 (10) years, with a mean forced expiratory volume in 1 s of 40 (6)% and a peak oxygen uptake of 67 (11)% of predicted values. Patients trained for 6 weeks on a cycle ergometer at high work-rates (WR). Near-infrared spectroscopy was used to obtain the time-constant of the deoxygenation recovery signal (tauHbO(2)) during three constant WR exercise tests, one below and two above the lactic acidosis threshold (theta(L)). Glycolytic and oxidative enzymes and lactate concentrations were assessed in muscle biopsies. The tauHbO(2) decreased significantly in all three constant WR tests: -18 (24)s, -20 (23) s and -13 (22) s, respectively. Endurance time increased in the higher WR tests, by 5.7 (4.8) min and 3.6 (2.7) min, respectively. The activity of citrate-synthase (CS) and creatine-kinase changed significantly from 20 (10) to 30 (13) micro mol x min(-1) x g(-1)and from 3.825 (950) to 3.402 (526) micro mol x min(-1) x g(-1), respectively. Training also improved significantly the mean response time of the on-transient of oxygen uptake (tau'VO(2)) of the below-theta(L) test. We found significant correlations between changes in CS and changes in tauHbO(2), tau'VO(2) and endurance time. We conclude that leg training accelerates the speed of re-oxygenation of the vastus lateralis muscle after exercise. This improvement is correlated to changes in the oxidative enzymes.
authors.affiliation: Servicio de Neumología, Hospital General Universitario Gregorio Marañón, calle Doctor Ezquerdo 46, 28007 Madrid, Spain. lpuente@separ.es
authors.forename: Luis
authors.initials: L
authors.lastname: Puente-Maestu
authors.forename: Tomás
authors.initials: T
authors.lastname: Tena
authors.forename: Carlos
authors.initials: C
authors.lastname: Trascasa
authors.forename: José
authors.initials: J
authors.lastname: Pérez-Parra
authors.forename: Raul
authors.initials: R
authors.lastname: Godoy
authors.forename: M José
authors.initials: MJ
authors.lastname: García
authors.forename: William W
authors.initials: WW
authors.lastname: Stringer
mesh_terms: D000222:Adaptation, Physiological; D002908:Chronic Disease; D015444:Exercise; D005081:Exercise Therapy / Q000379:methods*; D017079:Exercise Tolerance; D006801:Humans; D007717:Knee / Q000503:physiopathology; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000201:enzymology / Q000473:pathology / Q000503:physiopathology*; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption; D005082:Physical Exertion; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood / Q000503:physiopathology* / Q000534:rehabilitation*; D020127:Recovery of Function / Q000502:physiology; D012146:Rest
chemical_list: D010100:Oxygen