Inspiratory muscle training (IMT) involves breathing exercises using a pressure threshold device to strengthen the muscles involved in breathing in . IMT is safe and has not been shown to adversely affect patients’ heart rate, mean arterial pressure, or oxygen saturation measurements . It is a technique that has been widely applied to different populations, especially the general population of older adults . IMT is a promising tool for overall health management and has been reported to improve exercise capacity, functional anatomy, diaphragmatic thickness and mobility, and cardiac autonomic control .
Aging is associated with biological changes that compromise inspiratory muscle function and lung structure . It is reported that the strength of the inspiratory muscles declines gradually from 65 years of age onwards . Reduced respiratory strength has been identified as a risk factor for poor prognosis and mortality in many diseases . In older adults, there is an association between reduced respiratory muscle strength and diminished physical performance . Moreover, reduced respiratory strength is an independent risk factor for myocardial infarction and cardiovascular disease . A 2020 study sought to determine the isolated effects of IMT on general parameters of health in older adults (> 60 years) independently of their health condition . The results of the study revealed that IMT contributes to increasing the inspiratory muscle strength in older adults . In a separate 2019 study also focusing on the impact of IMT in older populations, IMT was associated with enhanced balance performance, which would reduce the likelihood of fatal and nonfatal injuries .
IMT has also been shown to improve the quality of life for people with heart failure . This disease causes a reduction in cardiac output and blood flow to the peripheral and respiratory muscles . The resulting muscle weakness is often associated with dyspnea, fatigue, reduced functional capacity, and increased exercise intolerance . IMT has been recommended as a therapy to improve cardiopulmonary capacity in patients with heart failure . The results of a 2020 study found that IMT increases inspiratory muscle strength, functional capacity, and quality of life in patients with heart failure . Notably, the benefits of IMT therapy were seen most in patients who used training loads higher than 60% and who had longer intervention times .
Respiratory muscle weakness is also observed in chronic obstructive pulmonary disease (COPD), and IMT has been associated with improvement in respiratory muscle functioning . COPD can lead to hypercapnia, dyspnea, nocturnal oxygen desaturation, and reduced exercise capacity . A meta-analysis of 18 studies revealed substantial evidence supporting the application of IMT in the treatment of COPD patients . Statistically significant improvements were observed for inspiratory muscle strength, endurance, functional capacity, dyspnea, and quality of life . The improvement in inspiratory muscle endurance capacity is thought to be due to an increase in the proportion of type I muscle fibers and the size of type II muscle fibers in the external intercostals, the muscles between the ribs, after IMT .
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