Effect of one-session and eight-week high-intensity interval training on gastrointestinal syndrome symptoms in female athletes

Gastrointestinal symptoms (increased intestinal damage, permeability & endotoxemia) are common and a limiting factor in acute, and prolonged strenuous exercises. Based on the ambiguous acute and chronic effects of high-intensity interval training (HIIT) on gastrointestinal function, this study was conducted to identify the effect of one-session and eight-week HIIT on some gastrointestinal syndrome markers in female athletes.

Twenty athlete’s girls participated in a quasi-experimental design that were allocated into equal groups: the control group (n=10) and HIIT (n=10). The single-session sports protecol consisted of 18 times of running 400 meters with an intensity of 100 to 110% of the maximal oxygen consumption, which increased from nine to 18 repetitions of 400 meters during the training period (eight weeks). Blood samples were collected immediately before and two hours after exercise protocols. Serum intestinal fatty acid-binding protein (I-FABP), Zonulin, lipopolysaccharide (LPS), and immunoglobulin M (IgM) markers were assessed using ELISA method. Data was analyzed using repeated-measures analysis of variance and Wilcoxon at a significance level of p<0.05.

One-session acute HIIT induced a significant decrease in IgM, and increases in I-FABP, Zonulin and LPS concentrations at the beginning and end of the training period (p<0.05). However, the acute increased response in Zonulin at the beginning; and Zonulin and IgM at the end of the training period returned to baseline levels after two hours of recovery. The LPS and IgM concentrations differences between the control and HIIT groups were not significant after eight weeks of training (p>0.05).

An acute HIIT session may increase permeability of I-FABP and gastrointestinal endotoxemia. However, the positive adaptations resulting from HIIT (eight weeks) can improve the exercise-induced response of intestinal integrity markers in female athletes.