Breathing pattern and thoracoabdominal motion in healthy individuals: influence of age and sex.

Objective: to describe the breathing pattern and thoracoabdominal motion of healthy individuals, taking age and sex into consideration.
Methods: the study included 104 individuals aged 20 to 39, 40 to 59, and 60 to 80 years (41 males and 63 females), with normal body mass index and spirometric values. Participants were evaluated at rest in the supine position, by means of respiratory inductive plethysmography. The following variables were measured: tidal volume (Vt), respiratory frequency (f), minute ventilation (VE), inspiratory duty cycle (Ti/Ttot), mean inspiratory flow (Vt/Ti), rib cage motion (%RC), inspiratory phase relation (PhRIB), expiratory phase relation (PhREB), and phase angle (PhaseAng). Comparisons between the age groups were performed using one-way ANOVA or Kruskal-Wallis H, while comparisons between the sexes were performed using Student's t test or the Mann-Whitney U test, depending on the data distribution; p<0.05 was taken to be significant.
Results: comparison between the sexes showed that, in the age groups 20 to 39 and 60 to 80 years, women presented significantly lower values for Vt, VE, and Ti/Ttot than men, and there was no significant difference in the age group 40 to 59 years. Comparisons between the age groups showed that participants aged 60 to 80 presented significantly greater PhRIB and PhaseAng than participants aged 20 to 39 years, without significant differences in the breathing pattern.
Conclusion: the data suggest that breathing pattern is influenced by sex whereas thoracoabdominal motion is influenced by age.