Summary
Research article
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Extract
Initial metabolic state and exercise-induced endotoxaemia are unrelated to gastrointestinal symptoms during exercise.
Introduction
Gastrointestinal symptoms (GIS) before, during, and after a competition are reported by approximately 20%-50% of the athletes participating in endurance events such as marathon, cycling and triathlon (Gil et al., 1998; Peters et al., 2001a). In spite of the high frequency of GIS such as bloating, side-pain, nausea, and diarrhea, the exact physiological mechanisms responsible for such disturbances are not fully-understood. Endotoxaemia has been suggested as an underlying cause responsible for the deleterious effect of strenuous physical exercise on athletes, who in extreme conditions might require medical attention (e.g., heat-stroke) (Hales and Sakurada, 1998; Ryan, 1993). Endotoxaemia is characterized by the presence of toxins in the blood, generally lipopolysaccharides (LPS) from gram-negative bacteria that bind to LPS-binding protein (LBP) to form the LPS-LBP complex (Triantafilou and Triantafilou, 2002). This complex is considered a marker of bacterial translocation and transport responsible for initiating a cell-mediated signal response (Nanbo et al., 1999; van Deventer et al., 1988; 1998; Camus et al., 1997). Large amounts of endotoxins normally reside within the human intestines. Bacterial translocation from the intestines to the portal circulation towards the liver might occur when factors such as a reduction in splanchnic blood flow, intense physical exercise, long stays at altitude, or high body core temperature affect the integrity of the intestinal wall (Hales and Sakurada, 1998; Hall et al., 2001; Peters et al., 2001a; Wagenmakers, 1992). During high-intensity and/or prolonged exercise blood flow to the splanchnic areas decreases by approximately 50% from the resting state (Pals et al., 1997). This reduction in blood flow is correlated to the intensity and duration of the exercise (Otte et al., 2001). A reduction in visceral blood flow might elicit intestinal ischemia, compromisi...See the full content of this document
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