To evaluate sarcopenic indices in relation to respiratory muscle strength (RMS) in elderly people.
This study included 65 volunteers over the age of 60 (30 men and 35 women). The skeletal muscle mass index (SMI) was measured using bioimpedance analysis. Limb muscle function was assessed by handgrip strength (HGS), the Short Physical Performance Battery (SPPB), and gait speed. RMS was addressed by maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) using a spirometer. The relationships between RMS and other sarcopenic indices were investigated using the Pearson correlation coefficients and multiple regression analysis adjusted for age, HGS, and SPPB.
Both MIP and MEP were positively correlated with SMI (r=0.451 and r=0.388, respectively, p<0.05 in both). HGS showed a significant correlation with both MIP and MEP (r=0.560, p<0.01 and r=0.393, p<0.05, respectively). There was no significant correlation between gait speed and either MIP or MEP. The SPPB was positively correlated with MEP (r=0.436, p<0.05). In the multiple regression analysis, MIP was significantly associated with HGS and SMI (p<0.001 and p<0.05, respectively), while MEP was related only with HGS (p<0.05).
This study suggests that respiratory muscles, especially inspiratory muscles, are significantly related to limb muscle strength and skeletal muscle mass. The clinical significance of MIP and MEP should be further investigated with prospective studies.
Citations
To compare the respiratory muscle strength between patients with stable and acutely exacerbated (AE) chronic obstructive pulmonary disease (COPD) at various stages.
A retrospective medical record review was conducted on patients with COPD from March 2014 to May 2016. Patients were subdivided into COPD stages 1–4 according to the Global Initiative for Chronic Obstructive Lung Disease guidelines: mild, moderate, severe, and very severe. A rehabilitation physician reviewed their medical records and initial assessment, including spirometry, maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP), COPD Assessment Test, and modified Medical Research Council scale. We then compared the initial parameters in patients with a stable condition and those at AE status.
The AE group (n=94) had significantly lower MIP (AE, 55.93±20.57; stable, 67.88±24.96; p=0.006) and MIP% (AE, 82.82±27.92; stable, 96.64±30.46; p=0.015) than the stable patient group (n=36). MIP, but not MEP, was proportional to disease severity in patients with AE and stable COPD.
The strength of the inspiratory muscles may better reflect severity of disease when compared to that of expiratory muscles.
Citations
To evaluate respiratory muscle strength in healthy Korean children in order to establish the criteria for normal reference values for future applications. In contrast with the other parameters for testing pulmonary function, normal values for respiratory muscle strength in healthy Korean children have not been assessed to date.
We conducted a complete survey of 263 students at Sinmyung Elementary School in Yangsan, Gyeongsangnam-do, and measured their height and body weight, performed pulmonary function tests, and evaluated maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) as measures of respiratory muscle strength. We excluded the subjects with respiratory or cardiovascular diseases that could affect the results. The subjects were children aged 8–12 years, and they consisted of 124 boys and 139 girls.
The MIP and MEP values (mean±standard deviation) for the entire subject group were 48.46±18.1 cmH2O and 47.95±16 cmH2O, respectively. Boys showed higher mean values for MIP and MEP in every age group. Korean children showed lower mean values for MIP and MEP compared to those in previous studies conducted in other countries (Brazil and USA).
Our results showed that boys generally have greater respiratory muscle strength than girls. We found a significant difference between the results of our study and those of previous studies from other countries. We speculate that this may be attributed to differences in ethnicity, nutrition, or daily activities.
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To investigate the relationships between respiratory muscle strength and conventional sarcopenic indices such as skeletal muscle mass and limb muscle strength.
Eighty-nine young adult volunteers who had no history of medical or musculoskeletal disease were enrolled. Skeletal muscle mass was measured by bioelectrical impedance analysis and expressed as a skeletal muscle mass index (SMI). Upper and lower limb muscle strength were evaluated by hand grip strength (HGS) and isometric knee extensor muscle strength, respectively. Peak expiratory flow (PEF), maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP) were evaluated using a spirometer to demonstrate respiratory muscle strength. The relationships between respiratory muscle strength and sarcopenic indices were investigated using Pearson correlation coefficients and multiple linear regression analysis adjusted by age, height, and body mass index.
MIP showed positive correlations with SMI (r=0.457 in men, r=0.646 in women; both p<0.01). MIP also correlated with knee extensor strength (p<0.01 in both sexes) and HGS (p<0.05 in men, p<0.01 in women). However, PEF and MEP had no significant correlations with these sarcopenic variables. In multivariate regression analysis, MIP was the only independent factor related to SMI (p<0.01).
Among the respiratory muscle strength variables, MIP was the only value associated with skeletal muscle mass.
Citations
Respiratory insufficiency is a common cause of morbidity and mortality in patients with Duchenne muscular dystrophy(DMD). In these patients, progressive muscle weakness is a major factor in the development of respiratory insufficiency. Therefore, the physical training program to improve the strength and endurance of respiratory muscle could conceivably improve respiratory function and prevent respiratory complication in patients with DMD.
The purpose of this study is to examine the effects of inspiratory muscle training on respiratory function of DMD patients according to functional state.
Eighteen DMD patients who were registered at the Muscle clinic of Yong Dong Severance Hospital were assessed for the pulmonary function using the routine pulmonary function test and measurements of maximal static pressures at 6 weeks before the training, at the beginning of training, and after the end of 6 week-training. The first 6 weeks were used as a control period. Inspiratory muscle training consisted of breathing through Threshold inspiratory muscle trainer (IMT) at 30% of patients' maximal inspiratory pressures(MIP) for 15 minutes twice a day and the 'endurance time' was recorded weekly for an assessment of inspiratory muscle endurance.
This study showed significant improvement of MIP and endurance time after the training in both ambulatory and wheelchair-bound patients. The amounts of improvement were greater in the patients with a better functional state and greater baseline forced vital capacity.
We conclude that, in the early stages of DMD, inspiratory muscle training with pressure threshold device is more useful when the forced vital capacity is well preserved.