Background: Irritable Bowel Syndrome (IBS) exerts a profound burden on Health-Related Quality of Life (HRQoL) and psychosocial well-being. While lifestyle changes are recommended, the dose–response relationship between physical activity (PA) intensities, symptom severity, and body image remains unclear. This study analyzed the interrelationships between PA intensities, symptom severity, body image satisfaction, and HRQoL in IBS patients. Methods: A cross-sectional study was conducted with 40 adult patients (60% female; 32.53 ± 12.54 years) diagnosed via Rome III/IV criteria. Validated instruments were used to assess PA (IPAQ-SF), sedentary behavior (SBQ), HRQoL (IBS-QoL), symptom severity (IBS-SSS), and body image (BIS). Data were analyzed using Quantile Regression, Robust Linear Regression, and Causal Mediation Analysis. Results: Participants reported moderate symptom severity (210.1 ± 79.2) and high sedentary time (511.1 ± 265.0 min/day). Quantile Regression showed no statistically significant associations between PA intensities and clinical severity (all p ≥ 0.289). PA did not moderate the negative relationship between pain and HRQoL (p = 0.738). However, symptom severity was a significant predictor of body dissatisfaction (β = 0.36, p < 0.001). A sexual dimorphism was observed, as women exhibited higher baseline dissatisfaction and greater sensitivity to symptom worsening than men (β = −0.50, p = 0.004). Conclusions: Symptom severity is strongly associated with body dissatisfaction in IBS, particularly among women, independent of nutritional status. While PA did not directly mitigate symptoms in this cohort, the significant relationship with body image underscores the need for clinical interventions to integrate psychosocial support to address perceptual vulnerability.
López-González et al. (Wed,) studied this question.