Abdominal breathing increases tear secretion in healthy women.

Purpose: To determine the relationship between abdominal breathing and tear meniscus volume in healthy women, we investigated the change in tear meniscus volume in two groups: normal breathing and abdominal breathing.

Methods: We used a crossover experimental model and examined 20 healthy women aged 20-54 years (mean ± SD, 32.7 ± 11.1 years). The participants were randomly assigned to one of two groups. During the first visit, the normal breathing group was subjected to normal breathing for 3 min, whereas the abdominal breathing group was subjected to abdominal breathing (4-second inhalation and 6-second exhalation) for 3 min. During the second visit, the protocols were swapped between the two groups. We estimated the R wave to R wave (R-R) interval, tear meniscus volume, salivary amylase activity, pulse, and blood pressure before and immediately after, 15 min after, and 30 min after completion of the breathing activity.

Results: After abdominal breathing, compared to that before breathing, the tear meniscus volume increased significantly 15 min after breathing (P<.01). Furthermore, systolic blood pressure showed a significant decrease immediately after abdominal breathing (P<0.05). No significant difference was found in the test parameters in the normal breathing group.

Conclusion: Abdominal breathing for 3 minutes increases the tear meniscus volume in healthy women. Consequently, abdominal breathing may be considered in the treatment of dry eye disease.