Irritable Bowel Syndrome in Athletes and Exercise:

Moderate-Intensity Physical Exercise Affects the Exercise Performance and Gut Microbiota of Mice

The gut microbiota is closely associated with the health of the host and is affected by many factors, including exercise. In this study, we compared the gut microbial changes and exercise performance over a 14-week period in mice that performed exercise (NE; n = 15) and mice that did not perform exercise (NC; n = 15). Mice were subjected to stool collection and exercise tests one week prior to adaptive training and after 2, 6, 10, and 14 weeks of exercise. Bacteria associated with the stool samples were assessed via Illumina-based 16S rRNA gene sequencing. While there was no significant difference in body weight between the groups (p > 0.05), the NE group had a significantly higher exercise performance from weeks 2-14 (p < 0.01) and lower fat coefficient (p < 0.01) compared with the NC group. The Shannon index of the gut microbiota in the NC group was higher than that in the NE group at weeks 6 and 10, and the Chao1 index was higher than that in the NE group at week 14. Exercise performance positively correlated with the relative abundance of Phascolarctobacterium. Grouped time series data analysis demonstrated that Bifidobacteria, Coprococcus, and one unnamed genus in the Clostridiales order were significantly increased in the NE group, which correlated with increased glucose, flavonoid, arginine, and proline metabolism. In conclusion, moderate-intensity treadmill exercise significantly increased the exercise performance of mice and changed the core bacteria and bacterial metabolic activity. These results provide a reference for studying the effects of exercise intervention and exercise performance on the gut microbiota of mice.

Applying a Low-FODMAP Dietary Intervention to a Female Ultraendurance Runner With Irritable Bowel Syndrome During a Multistage Ultramarathon

Malabsorption of fermentable oligo-, di-, mono-saccharides and polyols (FODMAPs) in response to prolonged exercise may increase incidence of upper and lower gastrointestinal symptoms (GIS), which are known to impair exercise performance. This case study aimed to explore the impact of a low-FODMAP diet on exercise-associated GIS in a female ultraendurance runner diagnosed with irritable bowel syndrome, competing in a 6-day 186.7-km mountainous multistage ultramarathon (MSUM). Irritable bowel syndrome symptom severity score at diagnosis was 410 and following a low-FODMAP diet (3.9 g FODMAPs/day) it reduced to 70. The diet was applied 6 days before (i.e., lead-in diet), and maintained during (5.1 g FODMAPs/day) the MSUM. Nutrition intake was analyzed through dietary analysis software. A validated 100-mm visual analog scale quantified GIS incidence and severity. GIS were modest during the MSUM (overall mean ± SD: bloating 27 ± 5 mm and flatulence 23 ± 8 mm), except severe nausea (67 ± 14 mm) experienced throughout. Total daily energy (11.7 ± 1.6 MJ/day) intake did not meet estimated energy requirements (range: 13.9-17.9 MJ/day). Total daily protein [1.4 ± 0.3 g·kg body weight (BW)^-1·day^-1], carbohydrate (9.1 ± 1.3 g·kg BW^-1·day^-1), fat (1.1 ± 0.2 g·kg BW^-1·day^-1), and water (78.7 ± 6.4 ml·kg BW^-1·day^-1) intakes satisfied current consensus guidelines, except for carbohydrates. Carbohydrate intake during running failed to meet recommendations (43 ± 9 g/hr). The runner successfully implemented a low-FODMAP diet and completed the MSUM with minimal GIS. However, suboptimal energy and carbohydrate intake occurred, potentially exacerbated by nausea associated with running at altitude.

Asymmetries in reciprocal baroreflex mechanisms and chronic pain severity: Focusing on irritable bowel syndrome

BACKGROUND

Objective measures of pain severity remain ill defined, although its accurate measurement is critical. Reciprocal baroreflex mechanisms of blood pressure (BP) control were found to impact differently on pain regulation, and thus their asymmetry was hypothesized to also connect to chronic pain duration and severity.

METHODS

Seventy-eight female patients with irritable bowel syndrome (IBS) and 27 healthy women were assessed for IBS severity and chronicity, negative affect, and various measures of resting autonomic function including BP, heart rate and its variability (HRV), baroreceptor-sensitivity to activations and inhibitions, gains of brady- and tachy-cardiac baro-responses, gains of BP falls/rises, and BP start points for these spontaneous baroreflexes.

KEY RESULTS

IBS directly and indirectly (through increased negative affect) was associated with asymmetry between baroreceptor activations/inhibitions compared to symmetrical baroreflex reciprocity in the healthy women. In the IBS group, independently of specific IBS symptoms, pain chronicity was associated with (i) decreased BP falls coupled with either (a) decreased tachycardia associated with lower disease severity (earlier "pain resilience" mechanism), or (b) decreased bradycardia associated with higher disease severity (later "pain decompensation" mechanism), or (ii) increased BP start point for baroreceptor activations coupled with either (a) BP increase (delayed "pain adaptation" mechanism) or (b) affect-related HRV decrease (delayed "pain aggravation" mechanism).

CONCLUSION AND INFERENCES

We anticipate the findings to be a starting point for validating these autonomic metrics of pain suffering and pain coping mechanisms in other chronic pain syndromes to suggest them as biomarkers of its severity and duration for profiling and correct management of chronic pain patients.

Gastrointestinal Conditions in the Female Athlete

Exercise can have significant effects on gastrointestinal diseases. Regular, moderate exercise can impart beneficial effects for the intestinal microbiome, irritable bowel syndrome symptoms, and inflammatory bowel disease. High-intensity training or prolonged endurance training, on the other hand, can have negative effects on these same entities. Female athletes report a higher prevalence of irritable bowel syndrome and celiac disease, and furthermore, have gastrointestinal symptoms modulated by the menstrual cycle. Management of gastrointestinal problems in the athletic population is widespread and includes training adjustments, dietary measures, and medicine management of symptoms.