Impact of mouth breathing on physical proficiency in children and adolescents: a cross-sectional study using the 6-minute walk test.

Mouth breathing (MB) is a concerning public health problem during childhood. The present cross-sectional study used the 6-minute walk test (6MWT) to compare the physical proficiency of children and adolescents who had a diagnosis of MB with that of children and adolescents who demonstrated nasal breathing (NB). A total of 80 patients aged 7 to 15 years were divided equally (n = 40) into MB and NB groups and underwent 2 6MWTs at 15-minute intervals. Cardiorespiratory variables--heart rate, respiratory rate, and peripheral oxygen saturation--were analyzed at 3 observation periods (OPs): OP0, baseline; OP1, after the first 6MWT; and OP2, after the second 6MWT. In addition, the distance traveled and the modified Borg scale (MBS) score, which measures perceived exertion, were recorded at OP1 and OP2. Statistical analyses included repeated-measures analysis of variance and t tests for continuous variables and the chi-square test for categorical variables, and the significance level was set at P < 0.05. Statistically significant increases in heart and respiratory rates from OP0 to OP2 were observed among both male and female patients in the MB group. Peripheral oxygen saturation showed a statistically significant increase from OP0 to OP2 among male patients in the MB group. Male patients in the MB group also showed significant increases in MBS scores from OP0 to OP1 and from OP0 to OP2. In female patients in the MB group, MBS scores increased significantly only from OP0 to OP2. Intergroup comparisons of mean values revealed statistically significant differences between male MB and NB patients for both the total distance covered and for MBS scores at both OP1 and OP2, with patients in the MB group traveling a shorter distance and reporting greater exertion. The present study established the utility of the 6MWT for assessment of physical proficiency in children and adolescents with varied breathing patterns. The results indicated that MB had a significant negative impact on physical proficiency in male children and adolescents. Female patients with a diagnosis of MB showed a clinical reduction in measures of physical proficiency, but the differences were not statistically significant.