Lactate

production and exercise-induced metabolic acidosis: guilty or not guilty? To the Editors: In the excellent and very interesting chapter concerning clinical exercise testing published in the European Respiratory Monograph on lung function testing, ROCA and RABINOVITCH [1] wrote the following. ‘‘Increased lactate production is responsible for the fall in muscle pH, which in turn may play a role in determining exercise intolerance in these patients (COPD patients). Premature lactic acidosis during exercise in COPD patients has been associated with reduced oxidative enzyme concentrations in the lower limb muscles.’’ We would like to emphasise that the widespread belief that lactic acid is produced in working muscles as a result o