Sports Performance Optimisation Research Team, School of Health Sciences, College of Health and Medicine, University of Tasmania, Launceston, Tasmania 7250, Australia.
Appl Physiol Nutr Metab. 2021 Sep;46(9):1105-1110. doi: 10.1139/apnm-2020-0883. Epub 2021 Mar 16.
Strenuous exercise increases gastrointestinal damage, but the dose-response relationship is yet to be elucidated. It is also commonly believed that running causes greater gastrointestinal damage than cycling. Two randomised, crossover studies aimed to 1) quantify gastrointestinal damage with increasing exercise intensity, and 2) determine if running was associated with greater gastrointestinal damage than cycling. Following a maximal oxygen uptake (O) test, participants completed 3 cycling trials at different intensities (60 min at 40%, 60% and 80% O; = 10 (5 female, 5 male)) (INTENSITY), or 1 running and 1 cycling trial (45 min at 70% O; = 11 (3 female, 8 male)) (MODE). Venous blood samples were collected pre- and post-exercise to measure gastrointestinal damage via intestinal fatty acid binding protein (I-FABP). In INTENSITY, I-FABP magnitude of change was greater at 80% O than 40% O ( < 0.01). In MODE, I-FABP magnitude of change was greater with cycling (mean (SD)) (84.7 (133.2)% = 1.07) compared with running (19.3 (33.1)%, = 0.65) with a moderate effect ( = 0.68, = 0.024). Rating of perceived exertion (RPE) and heart rate (HR) were higher during cycling (RPE < 0.0001; HR < 0.0001) but rectal temperature was not different between modes ( = 0.94). While gastrointestinal damage increases with increasing exercise intensity, running was not associated with greater gastrointestinal damage than cycling. A fraction of the anaerobic threshold, rather than a fraction of O, may be more predictive of intensity that results in exercise induced gastrointestinal damage. The mode of exercise may not be as important as intensity for inducing gastrointestinal damage. Improving anaerobic threshold may reduce susceptibility to gastrointestinal damage when exercising at high intensities.
剧烈运动增加胃肠道损伤，但剂量反应关系尚未阐明。人们普遍认为跑步比骑车造成更大的胃肠道损伤。两项随机交叉研究旨在 1）量化运动强度增加时的胃肠道损伤，2）确定跑步是否比骑车引起更大的胃肠道损伤。在最大摄氧量（O）测试后，参与者完成了 3 项不同强度的骑行试验（40%、60%和 80%O 的 60 分钟；n=10（5 名女性，5 名男性））（INTENSITY），或 1 次跑步和 1 次骑行试验（70%O 的 45 分钟；n=11（3 名女性，8 名男性））（MODE）。运动前后采集静脉血样，通过肠脂肪酸结合蛋白（I-FABP）测量胃肠道损伤。在 INTENSITY 中，80%O 时 I-FABP 变化幅度大于 40%O（<0.01）。在 MODE 中，与跑步相比，骑行时 I-FABP 变化幅度更大（平均（SD））（84.7（133.2）%n=1.07）（19.3（33.1）%n=0.65），具有中度效果（n=0.68，n=0.024）。骑行时的感觉用力评分（RPE）和心率（HR）更高（RPE<0.0001；HR<0.0001），但两种模式之间的直肠温度没有差异（n=0.94）。虽然运动强度增加会导致胃肠道损伤增加，但跑步并不比骑车更易引起胃肠道损伤。无氧阈的一部分，而不是 O 的一部分，可能更能预测导致运动引起的胃肠道损伤的强度。运动方式可能不如强度重要，因为运动方式可能不如强度重要。提高无氧阈可能会降低高强度运动时胃肠道损伤的易感性。
