; Miller et al., 2016 ). These discrepancies could be explained by various exercise protocols ( Afman et al., 2014 ), dosage ( Douroudos et al., 2006 ), gastrointestinal (GI) problems ( Burke & Pyne, 2007 ), or suboptimal timings of ingestion/individual variation in response to supplementation ( Sparks et
Anne Delextrat, Sinead Mackessy, Luis Arceo-Rendon, Aaron Scanlan, Roger Ramsbottom and Julio Calleja-Gonzalez
Ricardo J.S. Costa, Beat Knechtle, Mark Tarnopolsky and Martin D. Hoffman
) provide general guidance on race nutrition logistics, including the prevention and management of running-associated gastrointestinal symptoms. Physiological Demands Considering the multifactorial demands and challenges of competitive ultramarathon running, a wide array of factors underpin performance outcome
Brianna J. Stubbs, Pete J. Cox, Tom Kirk, Rhys D. Evans and Kieran Clarke
is gastrointestinal (GI) tolerability. For example, risk of severe GI side effects caused by sodium bicarbonate may limit its use, despite proven ergogenic effects ( Kahle et al., 2013 ; Peart et al., 2012 ). Symptoms have been reported following the consumption of KME at rest (mild flatulence
Stephanie K. Gaskell, Rhiannon M.J. Snipe and Ricardo J.S. Costa
Gastrointestinal symptoms (GIS) are a common feature of exercise, with prevalence data suggesting intensity and duration of exercise as major influential factors in the magnitude of GIS incidence and severity ( Costa et al., 2017c ). Consistently, >60% of ultraendurance athletes report GIS during
Alan J. McCubbin, Anyi Zhu, Stephanie K. Gaskell and Ricardo J.S. Costa
-associated gastrointestinal symptoms (GIS; Jeukendrup, 2014 ). More recently, there has been a focus on additional ingredients in CES to further improve gastric emptying, minimize GIS, and enhance carbohydrate absorption and oxidation during exercise ( Sutehall et al., 2018 ). Through the addition of alginate and pectin
Nancy J. Rehrer, Monique van Kemenade, Wineke Meester, Fred Brouns and Wim H.M. Saris
This study examined the relationship between gastrointestinal (GI) symptoms and dietary intake in triathletes. Fifty-five male triathletes (age 31 ±6 yrs) were surveyed regarding the most recently completed half Iron Man triathlon. Questions were asked regarding GI symptoms and dietary intake. Fifty-two percent complained of eructation and 48% of flatulence. Other symptoms were abdominal bloating, vomiting urge, vomiting, nausea, stomachache, intestinal cramps, and diarrhea. More symptoms occurred while running than at other times. All individuals who had eaten within 30 min of the start vomited while swimming. Fat and protein intake was greater in those who vomited or had the urge to vomit than in those without these symptoms. Of the former, 93% had consumed a hypertonic beverage. Forty percent of those who drank a hypertonic beverage and only 11% of those who drank an iso-or hypotonic beverage had severe complaints. Four of five individuals with stomachache had consumed a strongly hypertonic beverage. All subjects with intestinal cramps had eaten fiber-rich foods in the pre race meal; only 10% of those without cramps had done so.
Kristin J. Stuempfle, Martin D. Hoffman and Tamara Hew-Butler
Gastrointestinal (GI) distress is common during ultrarunning.
To determine if race diet is related to GI distress in a 161-km ultramarathon.
Fifteen (10 male, 5 female) consenting runners in the Javelina Jundred (6.5 loops on a desert trail) participated. Body mass was measured immediately prerace and after each loop. Runners reported if they had nausea, vomiting, abdominal cramps, and/or diarrhea after each loop. Subjects were interviewed after each loop to record food, fluid, and electrolyte consumption. Race diets were analyzed using Nutritionist Pro.
Nine (8 male, 1 female) of 15 runners experienced GI distress including nausea (89%), abdominal cramps (44%), diarrhea (44%), and vomiting (22%). Fluid consumption rate was higher (p = .001) in runners without GI distress (10.9 ± 3.2 ml · kg−1 · hr−1) than in those with GI distress (5.9 ± 1.6 ml · kg−1 · hr−1). Runners without GI distress consumed a higher percentage fat (p = .03) than runners with GI distress (16.5 ± 2.6 vs. 11.1 ± 5.0). In addition, fat intake rate was higher (p = .01) in runners without GI distress (0.06 ± 0.03 g · kg−1 · hr−1) than in runners with GI distress (0.03 ± 0.01 g · kg−1 · hr−1). Lower fluid and fat intake rates were evident in those developing GI distress before the onset of symptoms.
A race diet with higher percentage fat and higher intake rates of fat and fluid may protect ultramarathoners from GI distress. However, these associations do not indicate cause and effect, and factors other than race diet may have contributed to GI distress.
Charles S. Urwin, Dan B. Dwyer and Amelia J. Carr
Sodium citrate induces alkalosis and can provide a performance benefit in high-intensity exercise. Previous investigations have been inconsistent in the ingestion protocols used, in particular the dose and timing of ingestion before the onset of exercise. The primary aim of the current study was to quantify blood pH, blood bicarbonate concentration and gastrointestinal symptoms after ingestion of three doses of sodium citrate (500 mg⋅kg-1, 700 mg⋅kg-1 and 900 mg⋅kg-1). Thirteen participants completed four experimental sessions, each consisting of a different dose of sodium citrate or a taste-matched placebo solution. Blood pH and blood bicarbonate concentration were measured at 30-min intervals via analysis of capillary blood samples. Gastrointestinal symptoms were also monitored at 30-min intervals. Statistical significance was accepted at a level of p < .05. Both measures of alkalosis were significantly greater after ingestion of sodium citrate compared with placebo (p < .001). No significant differences in alkalosis were found between the three sodium citrate doses (p > .05). Peak alkalosis following sodium citrate ingestion ranged from 180 to 212 min after ingestion. Gastrointestinal symptoms were significantly higher after sodium citrate ingestion compared with placebo (p < .001), while the 900 mg.kg-1 dose elicited significantly greater gastrointestinal distress than 500 mg⋅kg-1 (p = .004). It is recommended that a dose of 500 mg⋅kg-1 of sodium citrate should be ingested at least 3 hr before exercise, to achieve peak alkalosis and to minimize gastrointestinal symptoms before and during exercise.
Xiaocai Shi, Mary K. Horn, Kris L. Osterberg, John R. Stofan,, Jeffrey J. Zachwieja, Craig A. Horswill, Dennis H. Passe and Robert Murray
This study investigated whether different beverage carbohydrate concentration and osmolality would provoke gastrointestinal (GI) discomfort during intermittent, high-intensity exercise. Thirty-six adult and adolescent athletes were tested on separate days in a double-blind, randomized trial of 6% and 8% carbohydrate-electrolytes (CHO-E) beverages during four 12-min quarters (Q) of circuit training that included intermittent sprints, lateral hops, shuttle runs, and vertical jumps. GI discomfort and fatigue surveys were completed before the first Q and immediately after each Q. All ratings of GI discomfort were modest throughout the study. The cumulative index for GI discomfort, however, was greater for the 8% CHO-E beverage than for the 6% CHO-E beverage at Q3 and Q4 (P < 0.05). Averaging across all 4 quarters, the 8% CHO-E treatment produced significantly higher mean ratings of stomach upset and side ache. In conclusion, higher CHO concentration and osmolality in an ingested beverage provokes stomach upset and side ache.
Beth Glace, Christine Murphy and Malachy McHugh
The purpose of this study was to document eating strategies employed by runners during a 160-km race, and to identify eating patterns that predispose the runner to disturbed mental or gastrointestinal functioning. We monitored intake in 19 volunteers during the 12 hours pre-race. Intake was determined by interview with runners approximately every 12 km throughout the race. The mean finish time was 24.3 hours, with 4 runners not completing the race. Body mass decreased during the race, 75.9 ± 2.3 kg to 74.4 ± 2.2 kg (p < .001). Runners ingested 2643 kcals during the 12 hours prerace (68% carbohydrate) and 3.8 L of fluid. During the race 6047 kcal, 18 L of fluid, and 12 g of sodium were consumed. Gastrointestinal distress (GI) was experienced by half of the participants, but was unrelated to food or fluid intake. Upper GI symptoms were more prevalent than lower and occurred mainly after 88 km. Runners with GI distress tended to complete fewer training miles (p = .10) and to do shorter training runs (p = .08). Half of the volunteers reported mental status changes (MSC), such as confusion or dizziness. Runners with MSC had greater intake of total calories, carbohydrate, and fluid (p < .05) than runners without MSC. They also completed shorter training runs (p = .03). Caloric and moisture intake for all runners far exceeded intakes described previously. Although intake did not match energy expenditure, it may represent the upper limit for absorption during exercise, and very high food and/or fluid intake appears to lead to perturbed mental status.