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Inspiratory muscle training in chronic airflow limitation: effect on exercise performance
C Lisboa1, C Villafranca, A Leiva
1Department of Respiratory Diseases, Catholic University of Chile, Santiago.
The European Respiratory Journal
|March 1, 1997
Summary
Inspiratory muscle training (IMT) using a higher load (30% peak maximal inspiratory pressure) improved exercise capacity and reduced breathlessness in patients with chronic airflow limitation. Lower loads did not yield significant benefits.
Area of Science:
- Pulmonary Rehabilitation
- Exercise Physiology
Background:
- The impact of inspiratory muscle training (IMT) on exercise capacity in patients with chronic airflow limitation (CAL) remains a subject of debate.
- Previous studies have yielded mixed results regarding the efficacy of IMT in improving exercise performance for individuals with CAL.
Purpose of the Study:
- To investigate the effects of different inspiratory muscle training (IMT) loads on exercise performance in patients with chronic airflow limitation (CAL).
- To assess changes in dyspnoea, exercise capacity (6-minute walk distance), and metabolic cost (oxygen consumption, minute ventilation) following IMT.
Main Methods:
- Twenty patients with CAL underwent a 10-week IMT program, training 30 minutes daily, 6 days a week.
- Two groups were formed: Group 1 trained at 30% of peak maximal inspiratory pressure (PI,max), and Group 2 trained at 10% of PI,max.
- Exercise performance was evaluated using the 6-minute walk distance (6MWD), progressive exercise testing (measuring V'O2 and V'E), and changes in PI,max and dyspnoea.
Main Results:
- Both training groups showed a significant increase in peak PI,max.
- Group 1 (30% PI,max) demonstrated significant improvements in reducing dyspnoea and increasing 6MWD (p<0.05 and p<0.01, respectively).
- Patients in Group 1 also exhibited a reduced minute ventilation (V'E) and oxygen consumption (V'O2) for the same exercise workload, indicating a lower metabolic cost.
Conclusions:
- Inspiratory muscle training (IMT) with a higher load (30% peak PI,max) is effective in improving exercise capacity and reducing the sensation of breathlessness in patients with CAL.
- This higher-intensity IMT also leads to a more efficient exercise metabolism, evidenced by reduced V'E and V'O2 at submaximal workloads.
- A training load of 10% peak PI,max did not result in significant improvements in exercise performance or dyspnoea in this patient population.