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 V_E (-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