Evidence regarding the association between exercise habits and irritable bowel syndrome (IBS) remains scarce in a young population. It is also unknown whether the existence of an exercise partner affects this issue. The purpose of this study was to explore the association between exercise habits that include an exercise partner and IBS in a young Japanese population.

This study enrolled 8923 Japanese university students and examined exercise frequency and intensity, and exercise partners using self-administered questionnaires. IBS and functional dyspepsia were defined according to the Rome III criteria.

The prevalence of IBS in this survey was 6.5%. Moderate frequency exercise was inversely related with IBS [adjusted odds ratio (aOR): 0.65 (95% confidence interval, CI: 0.51-0.83), P for trend = 0.005]. Moderate and high exercise intensities were independently and inversely related with IBS, respectively [aORs were moderate: 0.76 (95% CI: 0.61-0.95) and high: 0.62 (95% CI: 0.48-0.78), P for trend = 0.001]. Exercising with a group or with friends instead of alone was independently inversely related with IBS [aOR with groups: 0.53 (95% CI: 0.40-0.70) and with friends: aOR 0.71 (95% CI: 0.54-0.93)]. After excluding subjects with overlapping IBS and functional dyspepsia, an inverse association between high intensity of exercise or exercise in a group and IBS remained significant.

The frequency and intensity of exercise may be independently inversely related with IBS in a young Japanese population. Also, exercise with others may be important for preventing IBS.

Irritable bowel syndrome (IBS) is a common bowel disorder that manifests as unexplained abdominal pain or discomfort and bowel habit changes in the form of diarrhea, constipation, or alternating patterns of the two. Some evidences demonstrate that increased physical activity improves IBS symptoms. Hence, daily exercise is recommended in these patients. In this study, we aimed to investigate the relationship between physical activity and gastrointestinal symptoms in 101 university students (female = 78) with IBS. Participants were examined by Gastrointestinal Symptoms Rating Scale (GSRS), and gait steps were measured for 1 week using a pedometer. The association between the GSRS score and pedometer counts was determined by ordinal logistic modeling analysis. The ordinal logistic regression model for GSRS and locomotor activity showed a significant stepwise fit (z = -3.05, p = 0.002). The logistic curve separated GSRS score of 5 points (moderately severe discomfort) from 2 points (minor discomfort) by locomotor activity. The probability for daily locomotor activity to discriminate between 5 and 4 points of GSRS (i.e., likely to have reverse symptoms) decreased in accordance with increment of steps per day: 78% probability for 4000 steps, 70% probability for 6000 steps, 59% probability for 8000 steps, and 48% probability for 10000 steps. This study demonstrated that the severity of GSRS is associated with the amount of walking in younger people with IBS. These results may be used as a measure to determine the daily step count to reduce the severity of gastrointestinal symptoms in individuals with IBS.