Acute Effect of Trans-Spinal Direct Current Stimulation on Ventilatory Muscle Strength and Endurance in Young and Older Women

Abstract

Background:

Trans-spinal direct current stimulation (tsDCS) has been shown to impact diaphragm evoked potentials in young volunteers; however, it remains unclear if this translates into increased strength and ventilatory muscle function. This study aimed to evaluate whether an acute session of tsDCS can improve inspiratory muscle strength and ventilatory endurance in healthy young and older women.

Methods:

The study included healthy women aged 18–25 y and 60–80 y, who received either active or sham tsDCS applied over the C3–C5 cervical region. Inspiratory muscle strength was assessed by the S-index, whereas ventilatory endurance was evaluated using maximal voluntary ventilation (MVV). Data were compared using ANOVA two-way (between–within interaction), followed by post hoc pairwise tests, with Bonferroni correction for multiple comparisons, and statistical significance was set at P < .05.

Results:

Older women who received active tsDCS showed significant improvements in S-index (P = .01), with moderate effect sizes (Cohen’s D = 0.74). No significant changes were observed in young women, possibly because of a physiological ceiling effect. MVV did not differ between groups.

Conclusions:

tsDCS improved inspiratory muscle strength in older women only, suggesting its effectiveness may be greater in populations with age-related decline. Future studies should explore tsDCS in other populations, clinical conditions, and over repeated sessions.