Association Between Exercise-Induced Hyperthermia and Intestinal Permeability: A Systematic Review.

BACKGROUND

Prolonged and strenuous physical exercise increases intestinal permeability, allowing luminal endotoxins to translocate through the intestinal barrier and reach the bloodstream. When recognized by the immune system, these endotoxins trigger a systemic inflammatory response that may affect physical performance and, in severe cases, induce heat stroke. However, it remains to be elucidated whether there is a relationship between the magnitude of exercise-induced hyperthermia and changes in intestinal permeability.

OBJECTIVE

In this systematic review, we evaluated whether an exercise-induced increase in core body temperature (T ) is associated with an exercise-induced increase in intestinal permeability.

METHODS

The present systematic review screened the MEDLINE/PubMed and Web of Science databases in September 2016, without any date restrictions. Sixteen studies that were performed in healthy participants, presented original data, and measured both the exercise-induced changes in T and intestinal permeability were selected. These studies assessed intestinal permeability through the measurement of sugar levels in the urine and measurement of intestinal fatty acid binding protein or lipopolysaccharide levels in the blood.

RESULTS

Exercise increased both T and intestinal permeability in most of the 16 studies. In addition, a positive and strong correlation was observed between the two parameters (r = 0.793; p < 0.001), and a T exceeding 39 °C was always associated with augmented permeability.

CONCLUSION

The magnitude of exercise-induced hyperthermia is directly associated with the increase in intestinal permeability.