Maximal Inspiratory Pressure and Maximal Expiratory Pressure in Healthy Korean Children

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 cmH O and 47.95±16 cmH O, 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.