Arterial oxygen desaturation during treadmill and bicycle exercise in patients with chronic obstructive airways disease

• Published in: Clinical science (1979) Vol. 68; no. 3; pp. 327 - 332
• Main Authors: Cockcroft, A., Beaumont, A., Adams, L., Guz, A.
• Format: Journal Article
• Language: English
• Published: London Portland Press 01.03.1985
• Subjects: Aged; Biological and medical sciences; Carbon Dioxide - blood; Chronic obstructive pulmonary disease, asthma; Exercise Test; Humans; Lactates - blood; Lung Diseases, Obstructive - blood; Lung Diseases, Obstructive - physiopathology; Male; Medical sciences; Middle Aged; Oxygen - blood; Oxygen Consumption; Physical Exertion; Pneumology; Respiratory Function Tests; Physical exercise; Human; Arterial blood; Blood gas; Chronic; Oxygen; Lung function; Respiratory disease; Saturation; Bicycle ergometer; Exercise tolerance test; Obstructive pulmonary disease
• ISSN: 0143-5221; 1470-8736
• DOI: 10.1042/cs0680327

1. Nine men with severe chronic obstructive airways disease (COAD), known to desaturate on exercise, performed a 6 min self-paced walk on a treadmill, followed by a bicycle exercise with workloads adjusted to mimic the oxygen consumption achieved on the treadmill. During both exercises, ventilation, oxygen consumption, carbon dioxide production, Pao2, Paco2, pH and arterial lactate were measured and subjective breathlessness recorded. 2. A reasonable match of oxygen consumption between the two exercises was achieved. In all subjects Pao2 fell to a lower level during treadmill compared with bicycle exercise. Ventilation, carbon dioxide production and arterial lactate were higher during bicycle exercise. Subjective breathlessness was greater during bicycle exercise, in proportion to the higher ventilation on the bicycle. 3. The greater anaerobiosis occurring on the bicycle led to acidosis and an increased ventilation, minimizing the exercise fall in Pao2. 4. Bicycle testing may seriously underestimate exercise desaturation occurring during level walking in patients with severe COAD.