Association Between Exercise-Induced Hyperthermia and Intestinal Permeability: A Systematic Review
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.
In this systematic review, we evaluated whether an exercise-induced increase in core body temperature (T Core) is associated with an exercise-induced increase in intestinal permeability.
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 Core 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.
Exercise increased both T Core 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 Core exceeding 39 °C was always associated with augmented permeability.
The magnitude of exercise-induced hyperthermia is directly associated with the increase in intestinal permeability.
KeywordsLactulose Intestinal Permeability Bacterial Translocation Core Body Temperature Heat Stroke
The authors acknowledge M.S. James Jeremy McCormick for reviewing the manuscript.
Compliance with Ethical Standards
Christiano Veneroso, Gisele Vaz, and Washington Pires are recipients of post-doctorate fellowships from the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES/Brazil; AUX PE—PNPD—2251/2011), the Fundação de Amparo à Pesquisa do Estado de Minas Gerais (PMPD/FAPEMIG; BPD-00674-14), and the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq; 168145/2014-6), respectively. Diogo Pacheco is a recipient of a Master’s fellowship from CAPES. Samuel P. Wanner (CNPq; 473737/2013-2) and Fabiano T. Amorim (CNPq; 404201/2013-0) have grants to investigate the association between thermoregulatory and inflammatory responses during physical exercise and heat stress and thermoregulatory responses in workers, respectively. The funding institutions had no role in the study design, data analysis, decision to publish, or preparation of the article.
Conflict of interest
Washington Pires, Christiano Veneroso, Samuel Wanner, Diogo Pacheco, Gisele Vaz, Fabiano Amorim, Cajsa Tonoli, Danusa Soares, and Cândido Coimbra declare that they have no conflicts of interest relevant to the content of this review.
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