Because of this, the lack of correlation between lactate concentration and VE does not exclude the possibility that excessive lactate production may be associated with increased ventilatory requirement in some patients. Premature muscle lactic acidosis may also be involved in exercise intolerance in COPD, impairing muscle contractility and contributing to muscle fatigue .
We conclude that abnormal lactate kinetics are common in COPD patients with a wide range of disease severity and functional impairment. In our patients, reduction in functional status was associated with progressively greater increase in arterial blood lactate during exercise.
ACKNOWLEDGEMENTS: The authors thank Marthe Belanger, Marie-Josee Breton, and Alexandra Lauzier without whom this study could not have been completed, and Serge Simard for his statistical assistance. Dr Maltais is grateful to his colleagues from the Centre de Pneumologie de l’Hopital Laval for their support in his research. This study was supported in part by the Fonds de la recherche en sante du Quebec and by la fondation JD Begin, Universite Laval.