Effect of acute bicarbonate administration on exercise responses of COPD patients
| Autor: | Thomas J. Barstow, Eve Carithers, Remco Coppoolse, William W. Stringer, Richard Casaburi |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
Adult
Male medicine.medical_specialty Alkalosis Bicarbonate Physical Therapy Sports Therapy and Rehabilitation Physical exercise chemistry.chemical_compound Forced Expiratory Volume medicine Humans Orthopedics and Sports Medicine Lung Diseases Obstructive COPD Sodium bicarbonate Exercise Tolerance business.industry Respiration Venous blood medicine.disease Surgery Respiratory Function Tests Sodium Bicarbonate chemistry Anesthesia Breathing Exercise Test Arterial blood Female business |
| Zdroj: | Medicine and science in sports and exercise. 29(6) |
| ISSN: | 0195-9131 |
| Popis: | Patients with severe chronic obstructive pulmonary disease (COPD) are limited in their exercise tolerance by the level of ventilation (VE) they can sustain. We determined whether acutely increasing blood bicarbonate levels decreased acid stimulation to the respiratory chemoreceptors during exercise, thereby improving exercise tolerance. Responses were compared with those obtained during 100% O2 breathing (known to reduce VE in these patients) and to the responses of healthy young subjects. Participants were six patients with severe COPD (forced expired volume in 1 s = 31 +/- 11% predicted) but without chronic CO2 retention and 5 healthy young subjects. Each subject performed three incremental cycle ergometer exercise tests: 1) control, 2) after ingestion of 0.3 g.kg-1 of sodium bicarbonate and 3) while breathing 100% O2. During these tests VE was measured continuously and arterialized venous blood (patients) or arterial blood (healthy subjects) was sampled serially to assess acid base variables. Bicarbonate loading increased standard bicarbonate by 4-6 mmol.L-1 and this elevation persisted during exercise. In both groups, bicarbonate loading resulted in a substantially higher arterial pH; arterial PCO2 was either unchanged (healthy subjects) or mildly (averaging 5 torr) higher (COPD patients). However, in neither group did bicarbonate loading result in an altered VE response to exercise or an increase in exercise tolerance. In contrast, superimposing hyperoxia on bicarbonate ingestion yielded, on average, 24% reduction in VE and 50% increase in peak work rate in the patients (but not in the healthy young subjects). We conclude that acute bicarbonate loading is not an ergogenic aid in patients with severe COPD. |
| Databáze: | OpenAIRE |
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