title: Blood lactate and respiratory muscle fatigue in patients with chronic airways obstruction.
abstract: Blood lactate concentrations were measured in five patients with chronic airways obstruction after 10 minutes' sustained maximal voluntary ventilation (SMVV) with end-tidal carbon dioxide tension kept constant and after a 12-minute walk. No patient showed a significant rise in blood lactate after SMVV but all showed evidence of low-frequency fatigue of the sternomastoid muscle. After a 12-minute walk three patients showed a significant rise in blood lactate and two of them also had evidence of low-frequency fatigue of the sternomastoid muscle. The absence of a rise in blood lactate after SMVV may be due to the fact that in patients with chronic airways obstruction ventilation is limited by airflow obstruction to a level where only a small muscle mass is used, or where the aerobic capacity of the respiratory muscles is not exceeded.
mesh_terms: D000368:Aged; D006801:Humans; D007773:Lactates / Q000097:blood*; D019344:Lactic Acid; D008173:Lung Diseases, Obstructive / Q000097:blood* / Q000503:physiopathology; D008297:Male; D008451:Maximal Voluntary Ventilation; D008875:Middle Aged; D009132:Muscles / Q000503:physiopathology*; D005082:Physical Exertion; D012137:Respiratory System
chemical_list: D007773:Lactates; D019344:Lactic Acid