The present study investigated the effect of ingested fluid composition on the experience of exercise-related transient abdominal pain (ETAP). Forty subjects, susceptible to ETAP, completed 4 treadmill exercise trials: a no-fluid trial and flavored water (FW, no carbohydrate, osmolality = 48 mosmol/L, pH = 3.3), sports drink (SD, freshly mixed Gatorade®, 6% total carbohydrate, 295 mosmol/L, pH = 3.3), and reconstituted fruit juice (FJ, BERRI® orange, 10.4% total carbohydrate, 489 mosmol/L, pH = 3.2) trials. Measures of the experience of ETAP and gastrointestinal disturbances, particularly bloating, were quantified. The FJ was significantly (p < .01) more provocative of both ETAP and bloating than all other trials. There was no difference among the no-fluid, FW, and SD in the severity of ETAP experienced, although the difference between the no-fluid and SD approached significance at the .05 level (p = .056). There was a significant relationship between both the mean (r = 0.40, p < .01) and peak (r = 0.44, p < .01) levels of ETAP and bloating. When the level of bloating was controlled for, the FJ remained significantly (p < .01) more provocative of ETAP than the other conditions, with no difference between the FW and SD (p = .37). The results indicate that in order to avoid ETAP, susceptible individuals should refrain from consuming reconstituted fruit juices and beverages similarly high in carbohydrate content and osmolality, shortly before and during exercise. Further, the mechanism responsible for the heightened experience of ETAP in the FJ trial extends beyond a gastric mass explanation.
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Effect of Ingested Fluid Composition on Exercise-Related Transient Abdominal Pain
Darren Peter Morton, Luis Fernando Aragón-Vargas, and Robin Callister
Interaction Between Caffeine and Creatine When Used as Concurrent Ergogenic Supplements: A Systematic Review
Sara Elosegui, Jaime López-Seoane, María Martínez-Ferrán, and Helios Pareja-Galeano
mg·kg −1 , consumed 60 min before exercise are recommended by current guidelines ( Goldstein et al., 2010 ; Guest et al., 2021 ; Maughan et al., 2018 ; Pickering & Kiely, 2018 ), whereas doses above 9 mg·kg −1 provide no benefit and may cause side effects such as gastrointestinal distress
Effects of Bicarbonate, Citrate, and Phosphate Loading on Performance
Craig A. Horswill
Since the 1930s, scientists have attempted to determine if increasing the body’s ability to buffer metabolic acids will enhance physical performance. The buffer of major interest has been bicarbonate; to a lesser degree, citrate and phosphate salts have been investigated. In theory, the buffers facilitate performance by decreasing the accumulation of hydrogen ions that would otherwise presumably inhibit glycolysis and interfere with energy production or impair cross-bridge formation between myofilaments and thereby reduce force production. Literature findings indicate variable results, but overall it appears that bicarbonate salts taken at dosages of 0.3 g · kg−1 may improve performance during repeated sprints or at the end of a progressively more intense exercise test. Athletes are advised of potential ill effects of bicarbonate ingestion, such as gastrointestinal distress. Prior to applying the agents in a competitive setting, athletes should test the effects of buffers on performance during training sessions and consider the sport governing body’s stand on buffer usage.
Rationale for Upper Limits of Electrolyte Replacement during Exercise
Fred Brouns, Wim Saris, and Heinz Schneider
The addition of carbohydrate and sodium to sport drinks has been recommended to enhance fluid intake and absorption and to delay fatigue. Other electrolytes (E) which are lost through sweating are also commonly added. However, too many E may lead to increased serum E and osmolality levels, which may negatively influence thermoregulation, depress sweating, and cause gastrointestinal distress. On the other hand, drinking large amounts of plain water to compensate sweat loss may induce hyponatremia. Therefore, literature describing sweat E losses was examined in order to estimate average whole-body E loss and to determine an upper limit for replacement of E with sport drinks. Mean E loss was determined from 13 studies, with +1 SD resulting in a hypothetical range for E losses. Correction for net absorption resulted in an upper limit of electrolyte replacement. It is suggested that the E levels in sport rehydration drinks should not exceed the upper limit of the range given.
Induced Alkalosis and Gastrointestinal Symptoms After Sodium Citrate Ingestion: a Dose-Response Investigation
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.
Food and Fluid Intake and Disturbances in Gastrointestinal and Mental Function during an Ultramarathon
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.
Ketone Monoester Ingestion Alters Metabolism and Simulated Rugby Performance in Professional Players
Oliver J. Peacock, Javier T. Gonzalez, Simon P. Roberts, Alan Smith, Scott Drawer, and Keith A. Stokes
perceived exertion increased throughout the exercise protocol irrespective of trial (Figure 4a ), from initial values of 13 ± 1 ( fairly hard ) to 15 ± 2 ( hard ). As the time course of response was not different for ratings of gastrointestinal distress as well as drink pleasantness and acceptability, data
Acute Ketone Monoester Supplementation Impairs 20-min Time-Trial Performance in Trained Cyclists: A Randomized, Crossover Trial
Devin G. McCarthy, Jack Bone, Matthew Fong, Phillippe J.M. Pinckaers, William Bostad, Douglas L. Richards, Luc J.C. van Loon, and Martin J. Gibala
-hydroxybutyrate concentration in the range of 1–3 mM during an exercise may elicit the most favorable conditions for potential performance enhancement, perhaps by limiting the potential gastrointestinal distress, blood acidosis, and increased cardiorespiratory stress associated with relatively larger doses of KE supplements
The Effect of 1,3-Butanediol on Cycling Time-Trial Performance
David M. Shaw, Fabrice Merien, Andrea Braakhuis, Daniel Plews, Paul Laursen, and Deborah K. Dulson
in metabolic, cardiorespiratory, or performance variables were observed. These findings support previous work suggesting ketone supplements eliciting blood D-βHB concentrations up to ∼1 mmol/L do not benefit endurance performance. Furthermore, we found BD to elicit gastrointestinal distress, in
Effects of Caffeinated Gum on a Battery of Soccer-Specific Tests in Trained University-Standard Male Soccer Players
Mayur K. Ranchordas, George King, Mitchell Russell, Anthony Lynn, and Mark Russell
buccal mucosa) than capsules and drinks and less likely to cause gastrointestinal distress. Accordingly, this may be beneficial for team sport athletes where there is limited time for nutrition intervention during competition such as at half-time where only 10 min are available to administer a