Effects of a Four-Week Combined Respiratory Muscle Training and Breathing Exercise Program on Breath-Holding Time, Functional Performance, Sleep Quality, and Perceived Stress in Healthy University Students

Background: Breathing exercises and respiratory muscle training (RMT) are accessible, low-cost interventions that may improve both physical and psychological health through respiratory and autonomic regulation. Despite growing interest in respiratory interventions, their combined effects on physical performance, sleep quality, and perceived stress in healthy university students remain poorly understood. Methods: This pilot pre-post experimental study was conducted in Saudi Arabia. Students aged 18–25 years with a BMI < 29.9 kg/m2 participated in a 4-week intervention consisting of diaphragmatic breathing, pursed-lip breathing, and threshold-loaded inspiratory and expiratory muscle training (40–60% maximal inspiratory pressure), performed five days per week. Outcomes assessed before and after the intervention included chest expansion, breath-holding time, Timed Up-and-Go (TUG), Sit-to-Stand (STS), Pittsburgh Sleep Quality Index (PSQI), and Perceived Stress Scale (PSS). Paired statistical analyses and correlation tests were performed. Results: Forty participants (50% female; median age 22 years; BMI 23.14 ± 4.05 kg/m2) completed the study. Breath-holding time increased by 132% (p < 0.001, r = 0.87). Functional performance improved significantly, with TUG decreasing by 9% (d_z = 1.01) and STS improving by 12% (d_z = 1.12) (p < 0.001). Sleep quality improved by 26%, while perceived stress decreased by 19% (p ≤ 0.001). Significant exploratory correlations were observed between TUG and STS change scores (r = 0.49), PSQI and PSS changes (r = 0.33), and STS and PSS changes (r = 0.33). Conclusions: Participation in a four-week combined breathing exercise and respiratory muscle training program was associated with favorable within-group changes in breath-holding time, functional performance, sleep quality, and perceived stress among healthy university students. Given the single-arm design, these findings should be considered preliminary and hypothesis-generating. Randomized controlled studies are needed to determine efficacy and causal relationships.