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Two weeks of repetitive gut‐challenge reduce exercise‐associated gastrointestinal symptoms and malabsorption
Author(s) -
Miall A.,
Khoo A.,
Rauch C.,
Snipe R. M. J.,
CamõesCosta V. L.,
Gibson P. R.,
Costa R. J. S.
Publication year - 2018
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/sms.12912
Subject(s) - medicine , placebo , gastrointestinal function , nausea , carbohydrate , gastroenterology , malabsorption , fructose , food science , chemistry , alternative medicine , pathology
Debilitating gastrointestinal symptoms is a common feature of endurance running and may be exacerbated by and/or limit the ability to tolerate carbohydrate intake during exercise. The study aimed to determine whether two weeks of repetitive gut‐challenge during running can reduce exercise‐associated gastrointestinal symptoms and carbohydrate malabsorption. Endurance runners ( n =18) performed an initial gut‐challenge trial ( GC 1) comprising 2‐hour running exercise at 60% VO 2max (steady state) while consuming a formulated gel‐disk containing 30 g carbohydrates (2:1 glucose‐fructose, 10% w/v ) every 20 minutes, followed by a 1‐hour running effort bout. Gastrointestinal symptoms, feeding tolerance, and breath hydrogen (H 2 ) were determined along the gut‐challenge trial. After GC 1, participants were randomly assigned to a blinded carbohydrate ( CHO , 90 gCHO hour −1 ) or placebo ( PLA , 0 gCHO hour −1 ) gut‐training group. This comprised of consuming the group‐specific feeding intervention during 1‐hour running exercise at 60% VO 2max equivalent, daily over a period of two weeks. Participants then repeated the gut‐challenge trial ( GC 2). In GC 2, a reduced gut discomfort ( P =.012), total ( P =.009), upper‐ ( P =.015), and lower‐gastrointestinal ( P =.008) symptoms, and nausea ( P =.05) were observed on CHO , but not PLA . Feeding tolerance did not differ between GC 1 and GC 2 on CHO and PLA . H 2 peak was attenuated in GC 2 (6±3 ppm) compared to GC 1 (13±6 ppm) on CHO ( P =.004), but not on PLA ( GC 1 11±7 ppm, and GC 2 10±10 ppm). The effort bout distance was greater in GC 2 (12.3±1.3 km) compared with GC 1 (11.7±1.5 km) on CHO ( P =.035) only. Two weeks of repetitive gut‐challenge improve gastrointestinal symptoms and reduce carbohydrate malabsorption during endurance running, which may have performance implications.