Cognitive function and blood-brain barrier permeability during exercise in the heat: Effect of fitness and bovine colostrum supplementation

详细信息    查看全文

• 作者：Shawnda A. Morrison ; Stephen S. Cheung ; Roger D. Hurst ; James D. Cotter
• 关键词：Stroop test ; S100¦Â ; Aerobic fitness ; Heat stress ; Perceived exertion
• 刊名：Journal of Thermal Biology
• 出版年：2013
• 出版时间：October, 2013
• 年：2013
• 卷：38
• 期：7
• 页码：374-383
• 全文大小：1167 K

文摘

We investigated whether fitness and bovine colostrum supplementation modulates cognition and cerebrovascular function during exercise in the heat in this placebo-controlled, double-blind study. Seven highly-fit (HF, 64¡À4 mL kg^?1 min^?1) and eight moderately-fit (MF, 46¡À4 mL kg^?1 min^?1) men completed two randomised, 90-min exercise bouts (30 ¡ãC, 50 % RH) after 7-d of bovine colostrum supplementation (COL: 1.7 g kg^?1 d^?1) or placebo (CON: cornflour). Multi-mode exercise consisted of: 15-min fixed-load cycling at 50 % heart rate reserve (HRR; Cycle1), 30-min fixed-speed running (80 % HRR; Run1), 30-min time trial (Run2), then repeating cycling (Cycle2). Heart rate, end-tidal PCO₂, cerebral oxygenation, a marker of blood-brain barrier integrity ([S100?]), cognition (Stroop test) and perceptions were recorded at rest, Cycles1 and 2, and 5 h post-exercise. MF had less cerebral deoxygenation during exercise (MF: ?5¡À14, HF: 8¡À7 ¦ÌM L^?1), but [S100?] was unchanged across fitness and colostrum supplementation. Hypocapnia was evident from Cycle1 to Run2 with end-tidal PCO₂ decreasing from 36¡À5 to 31¡À5 mmHg in both trials. Response time to simple and complex tasks decreased during exercise by ~83 and ~301 ms, compared to rest in both fitness groups in both trials. The time difference between complex and simple tasks (i.e. decision-making time) also decreased from 724¡À200 (Rest) to 552¡À326 (Cycle1), 565¡À148 (Cycle2) and 515¡À216 ms (post-exercise; pooled results). We conclude that fitness per se does not modulate cognitive executive function or blood-brain barrier permeability during comparable, relative-intensity exercise in the heat, and that colostrum supplementation had negligible effect on performance, cognitive or cerebrovascular functioning.