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Exercise-limiting factors in respiratory distress
J Karlsson1, B Diamant, K Folkers
1Department of Clinical Physiology, Karolinska Institute, Stockholm, Sweden.
Respiration; International Review of Thoracic Diseases
|January 1, 1992
Summary
Chronic obstructive pulmonary disease (COPD) reduces physical performance due to muscle changes and impaired circulation. Antioxidant deficiencies may worsen muscle trauma in COPD patients, impacting exercise capacity.
Area of Science:
- Pulmonary Medicine
- Exercise Physiology
- Muscle Biology
Background:
- Chronic obstructive pulmonary disease (COPD) is characterized by reduced physical performance, dyspnea, muscle wasting, and malnutrition.
- Impaired right ventricular circulatory function is a key factor in COPD-related exercise limitation.
- Muscle fiber composition, particularly the shift towards fast-twitch (FT) fibers, is implicated in reduced physical capacity.
Purpose of the Study:
- To review exercise performance data, circulatory function, and muscle quality in COPD patients.
- To identify potential limiting factors for physical performance in COPD.
- To explore the role of muscle fiber type and antioxidant status in COPD pathophysiology.
Main Methods:
- Review of existing literature on exercise performance, circulatory function, and muscle quality in COPD.
- Analysis of muscle fiber composition (FT vs. slow-twitch/ST) and its relation to performance.
- Assessment of antioxidant levels (CoQ10, alpha-tocopherol) in leg muscles and plasma.
Main Results:
- COPD patients exhibit reduced physical performance, often linked to impaired circulatory and respiratory function.
- A higher proportion of FT muscle fibers is observed in COPD, potentially due to genetic factors, hypoxic effects, or muscle trauma.
- Lower antioxidant levels (CoQ10, alpha-tocopherol) are found in COPD and ischemic heart disease (IHD) patients, suggesting increased susceptibility to oxidative stress and trauma, particularly in ST fibers.
Conclusions:
- Muscle quality, including fiber type distribution and antioxidant status, significantly impacts physical performance in COPD.
- The observed FT fiber preponderance and reduced antioxidants may contribute to exercise intolerance in COPD.
- Further research is needed to investigate the efficacy of antioxidant supplementation (e.g., CoQ10) in improving muscle function and exercise performance in COPD patients.