Gastrointestinal disturbances are one of the most common issues for endurance athletes during training and competition in the heat. The relationship between typical dietary intake or nutritional interventions and perturbations in or maintenance of gut integrity is unclear. Twelve well-trained male endurance athletes (peak oxygen consumption = 61.4 ± 7.0 ml·kg⁻¹·min⁻¹) completed two trials in a randomized order in 35 °C (heat) and 21 °C (thermoneutral) conditions and kept a detailed nutritional diary for eight consecutive days between the two trials. The treadmill running trials consisted of 15 min at 60% peak oxygen consumption, 15 min at 75% peak oxygen consumption, followed by 8 × 1-min high-intensity efforts. Venous blood samples were taken at the baseline, at the end of each of the three exercise stages, and 1 hr postexercise to measure gut integrity and the permeability biomarker concentration for intestinal fatty-acid-binding protein, lipopolysaccharide, and lipopolysaccharide-binding protein. The runners self-reported gut symptoms 1 hr postexercise and 3 days postexercise. The heat condition induced large (45–370%) increases in intestinal fatty-acid-binding protein, lipopolysaccharide-binding protein, and lipopolysaccharide concentrations compared with the baseline, but induced mild gastrointestinal symptoms. Carbohydrate and polyunsaturated fat intake 24 hr preexercise were associated with less lipopolysaccharide translocation. Protein, carbohydrate, total fat, and polyunsaturated fat intake (8 days) were positively associated with the percentage increase of intestinal fatty-acid-binding protein in both conditions (range of correlations, 95% confidence interval = .62–.93 [.02, .98]). Typical nutrition intake partly explained increases in biomarkers and the attenuation of symptoms induced by moderate- and high-intensity exercise under both heat and thermoneutral conditions.

肠胃不适是耐力运动员在高温训练和比赛中最常见的问题之一。典型的饮食摄入或营养干预与肠道完整性的扰动或维持之间的关系尚不清楚。12 名训练有素的男性耐力运动员（峰值耗氧量 = 61.4 ± 7.0 ml·kg ^-1 ·min ^-1) 在 35°C（热）和 21°C（热中性）条件下以随机顺序完成两项试验，并在两次试验之间连续八天保持详细的营养日记。跑步机跑步试验包括 60% 峰值耗氧量 15 分钟、75% 峰值耗氧量 15 分钟，然后是 8 × 1 分钟的高强度努力。在基线、三个运动阶段结束时和运动后 1 小时采集静脉血样，以测量肠道完整性和肠道脂肪酸结合蛋白、脂多糖和脂多糖结合蛋白的渗透性生物标志物浓度。跑步者在运动后 1 小时和运动后 3 天自我报告肠道症状。热条件导致肠道脂肪酸结合蛋白、脂多糖结合蛋白、和脂多糖浓度与基线相比，但诱发轻度胃肠道症状。运动前 24 小时摄入的碳水化合物和多不饱和脂肪与较少的脂多糖易位有关。在两种情况下，蛋白质、碳水化合物、总脂肪和多不饱和脂肪摄入量（8 天）与肠道脂肪酸结合蛋白的百分比增加呈正相关（相关范围，95% 置信区间 = .62–.93 [. 02, .98])。典型的营养摄入部分解释了在热和热中性条件下中高强度运动引起的生物标志物增加和症状减轻。运动前 24 小时摄入的碳水化合物和多不饱和脂肪与较少的脂多糖易位有关。在两种情况下，蛋白质、碳水化合物、总脂肪和多不饱和脂肪摄入量（8 天）与肠道脂肪酸结合蛋白的百分比增加呈正相关（相关范围，95% 置信区间 = .62–.93 [. 02, .98])。典型的营养摄入部分解释了在热和热中性条件下中高强度运动引起的生物标志物增加和症状减轻。运动前 24 小时摄入的碳水化合物和多不饱和脂肪与较少的脂多糖易位有关。在两种情况下，蛋白质、碳水化合物、总脂肪和多不饱和脂肪摄入量（8 天）与肠道脂肪酸结合蛋白的百分比增加呈正相关（相关范围，95% 置信区间 = .62–.93 [. 02, .98])。典型的营养摄入部分解释了在热和热中性条件下中高强度运动引起的生物标志物增加和症状减轻。95% 置信区间 = .62–.93 [.02, .98]）。典型的营养摄入部分解释了在热和热中性条件下中高强度运动引起的生物标志物增加和症状减轻。95% 置信区间 = .62–.93 [.02, .98]）。典型的营养摄入部分解释了在热和热中性条件下中高强度运动引起的生物标志物增加和症状减轻。