The Science Journal of the American Association for Respiratory Care

1999 OPEN FORUM Abstracts

ANALYSIS OF CONSTANT WORK EXERCISE TO EVALUATE THE EFFECT OF THE PHYSICAL TRAINING IN THE CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD)

F Burgos, E Sala, RM Marrades,, J Roca, A Moreno, J Alonso, JM González de Suso, JA Barbera, R Rodriguez-Roisin and PD Wagner. S de Pneumologia, Hospital Clínic, Universitat de Barcelona y Centre Diagnostic Pedralbes, Barcelona, España. Dpt. of Physiology, University of California, San Diego, La Jolla, CA, USA.

The effect of a program of physical training was analyzed with high work intensity (>70% of the VO2 pick) of eight weeks of duration in patient with COPD (n=8, 64±4) years; FEV1 45±11% pred; PaO2, 71±8 mmHg; and, PaCO2 35±3 mmHg), by an exercise to constant load of low intensity. Before and after the training were measured: 1) whole-body uptake (VO2) during an incremental exercise with cycloergometer; 2) VO2 during submaximal exercise constant work rate to 20%, 40% and 60% of maximal exercise pre-training; and, 3) 31 phosphor spectroscopy (31P-NMRS) of the femoral quadriceps during the exercise. After the training, the incremental exercise only detected a significant increase of the maximal work (+15±1.9 watts) (p = 0.005). However, the exercise to constant work rate (40% of the maximum work pre-training) showed: 1) improvement in the kinetics of the VO2 (the time constant of the VO2 diminished -11±8 s-1) (p = 0.003); and, 2) decrease of the VO2 (-102±56 mL.min-1) (p = 0.001), VCO2 (-102±62 mL.min-1) (p = 0.002) and VE (-2.0±1.3 L.min-1) (p = 0.05) to the four minutes of beginning of the submaximal exercise. The 31P-NMRS also showed training effect for the decrease of the half time recovery of phosphocreatinine (from 50±8 to 34±7 s) (p=0.02), and increasing the intracellular pH (from 6.83 to 6.98) (p=0.04) and decrease the relationship of P/[PCr] (from 1.6±0.9 to 0.8±0.7) (p=0.05) to a certain submaximal exercise. Also, the fall of the VO2 observed after the physical training were correlated with the increment of the intracellular pH (r = 0.78). An association was observed among the improvement of the kinetics of the VO2 to constant work with the reduction of the constant of time of the recovery of the [PCr] after the training. We conclude that: 1) the exercise to constant work can be useful for the evaluation of the results of a program of physical training in patient with COPD; and, 2) the correlation among fall of the VO2 and the increase of the intracellular pH, suggests that the effect of the physical training would take place, mainly, at level of the skeletal muscle. (Supported in part by: FIS 97-0794, 1997 SGR-008)

OF-99-069

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