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Date of Graduation
5-12-2022
Semester of Graduation
Spring
Degree Name
Master of Science (MS)
Department
Department of Kinesiology
Second Advisor
Nicholas D. Luden
Third Advisor
Christopher J. Womack
Abstract
PURPOSE: The utilization of hydrogel technology allows carbohydrate beverages to form a gel in the acidic environment of the stomach, potentially enhancing gastric emptying. However, few studies have researched the effects of these beverages on gastrointestinal (GI) tolerance and exercise performance; there is minimal data in a variety of exercise conditions and/or beverage ingestion rates. The purpose of the present study was to assess the effects of a 80 g/h of maltodextrin-fructose hydrogel (MF-H) beverage versus conventional carbohydrate sources on GI symptoms and running performance. METHODS: eight distance runners (26 ± 5 y; VO2max = 65 ± 7 ml/kg/min) completed a prolonged running protocol [90 min at 70% VO2max + an incremental-intensity test to fatigue (TTF)] on three occasions. One of the following beverages was consumed during each trial: a) MFH, b) isocaloric maltodextrin-fructose (MF), or c) isocaloric maltodextrin-only (MD). Beverages were double-blinded and provided in randomly counterbalanced order. 125 mL of each beverage were consumed immediately prior to exercise, and again at 15 min intervals, providing 80 g CHO/h. Physiological measures (VO2, RER, heart rate, blood glucose, and lactate) and GI symptom ratings (nausea, fullness, abdominal cramps) were assessed at 30 min intervals throughout exercise and during the TTF test. Treatment effects were examined using repeated-measures ANOVA’s (treatment x time). RESULTS: VO2, heart rate, and blood glucose increased (p < 0.05) over time during exercise, with no treatment or treatment*time effects. Similarly, all GI symptoms increased in severity over time (to low-moderate levels) with no differences between treatments, with the exception that the fullness rating during the TTF was higher in the MF trial (6.2 ± 2.4) versus MD (4.1 ± 3.0), and also trended (p < 0.1) higher than MFH (4.2 ± 3.3). No differences in TTF (p = 0.890) were observed between MD (551 ± 212 s), MF (555 ± 230 s) and MFH (540 ± 165 s). CONCLUSIONS: Under the present conditions (moderate intensity running in thermoneutral conditions consuming carbohydrate at ingestion rates of ~80 g/h), a carbohydrate hydrogel beverage provided no meaningful effects on physiological responses, gastrointestinal symptoms, or running performance versus conventional carbohydrate beverages.
