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Pathophysiological factors which limit the exercise capacity of the sick child
Insights
Sick children
Area of Science:
- Pediatric Exercise Physiology
- Clinical Pathophysiology
Background:
- Exercise performance deficits in sick children stem from inactivity and detraining.
- Specific pathophysiological factors also impair physical fitness components.
Purpose of the Study:
- To explore the pathophysiological causes of exercise intolerance in pediatric populations.
- To identify specific fitness components affected by various diseases.
Main Methods:
- Analysis of factors affecting maximal aerobic power (e.g., stroke volume, heart rate, O2 content).
- Evaluation of O2 cost of locomotion and muscle strength.
- Assessment of local muscle endurance using the Wingate anaerobic test.
Main Results:
- Low maximal aerobic power can result from cardiac issues, low O2 transport, or high O2 cost of locomotion (e.g., obesity, cerebral palsy).
- Subnormal muscle strength impacts daily functions in conditions like muscular dystrophy and juvenile rheumatoid arthritis.
- Neuromuscular diseases show deficient local muscle endurance and a lower peak anaerobic to aerobic power ratio.
Conclusions:
- Pathophysiological factors significantly contribute to exercise limitations in sick children.
- Understanding these specific deficits is crucial for targeted interventions and improving physical function.
Abstract:
While deficient exercise performance of sick children results from hypoactivity and detraining, it can also be caused by specific pathophysiological factors. These can affect one or more components of physical fitness. A low maximal aerobic power will result from a low maximal stroke volume, as in aortic stenosis or cardiomyopathy; a low maximal heart rate, as in congenital complete heart block or intake of beta-blockers; a low O2 content of the arterial blood, as in anemia or advanced cystic fibrosis; and a high O2 content of mixed-venous blood, as in muscle atrophy or severe malnutrition. A high O2 cost of locomotion, as in advanced obesity or cerebral palsy, will cause the patient to exert at a high percentage of his maximal aerobic power and thus fatigue easily. A subnormal muscle strength, as in progressive muscular dystrophy or juvenile rheumatoid arthritis, is sometimes the primary factor that limits the walking ability or other daily functions. Recent data suggest that local muscle endurance, as assessed by the Wingate anaerobic test, is particularly deficient in some neuromuscular diseases. Examples are muscular dystrophies and spastic cerebral palsy. The ratio of peak anaerobic power to peak aerobic power seems lower in such patients than in able-bodied controls.