Document Detail


Symptoms, lactate and exercise limitation at peak cycle ergometry in adults with cystic fibrosis.
MedLine Citation:
PMID:  15929961     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The purpose of this study was to investigate symptoms, lactate accumulation and limiting factors at peak exercise in cystic fibrosis (CF) patients. In total, 104 CF adults attending an adult CF centre and 27 controls performed progressive cycle ergometry to a symptom-limited maximum. Measurements taken at peak exercise included: heart rate, ventilation, oxygen uptake, carbon dioxide output, oxygen saturation and blood lactate. Symptom scores of perceived breathlessness and muscle effort were recorded using Borg scales. The CF subjects had a lower mean body mass index, forced expiratory volume in one second (FEV(1)) and peak oxygen uptake than controls. Peak lactate concentrations were very similar to controls (mean+/-sd 6.8+/-2.0 mmol x L(-1) versus 7.4+/-1.0 mmol x L(-1)). Symptom scores were no different to controls for either breathlessness (4.5+/-2.0 versus 4.3+/-1.0) or perceived muscle effort (6.1+/-2.0 versus 6.5+/-1.0), with higher scores for muscle effort than breathlessness in both groups. In addition, peak ventilation was lower than the predicted maximum, and high peak heart rates were recorded supporting nonpulmonary factors as important in limiting peak exercise. Peak oxygen uptake was correlated with FEV(1). Comparison of CF subjects with mild or moderate pulmonary disease and controls revealed similar exercise responses. In contrast, those CF patients with severe lung disease (FEV(1) <40% predicted) had significantly higher breathlessness, lower muscle effort scores, lower peak lactate, lower peak heart rate and a mean ventilation exceeding predicted, thus confirming that ventilation was the major factor limiting exercise. In conclusion, cystic fibrosis subjects have a reduced peak exercise capacity, but their exercise response is similar to controls in generating high blood-lactate concentrations and symptoms of muscle effort in excess of dyspnoea. Nonpulmonary factors influence peak performance more in those without severe disease.
Authors:
A J Moorcroft; M E Dodd; J Morris; A K Webb
Publication Detail:
Type:  Clinical Trial; Controlled Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The European respiratory journal : official journal of the European Society for Clinical Respiratory Physiology     Volume:  25     ISSN:  0903-1936     ISO Abbreviation:  Eur. Respir. J.     Publication Date:  2005 Jun 
Date Detail:
Created Date:  2005-06-02     Completed Date:  2005-09-27     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8803460     Medline TA:  Eur Respir J     Country:  Denmark    
Other Details:
Languages:  eng     Pagination:  1050-6     Citation Subset:  IM    
Affiliation:
Manchester Adult Cystic Fibrosis Centre, Wythenshawe Hospital, South Manchester, M23 9LT, UK.
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MeSH Terms
Descriptor/Qualifier:
Adult
Cystic Fibrosis / blood,  classification,  physiopathology*
Dyspnea / diagnosis,  etiology
Exercise Test*
Exercise Tolerance* / physiology
Female
Humans
Lactic Acid / blood*
Lung / physiopathology*
Male
Muscle Fatigue / physiology
Oxygen Consumption / physiology
Respiratory Function Tests
Chemical
Reg. No./Substance:
50-21-5/Lactic Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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