Theses and Dissertations at Montana State University (MSU)
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Item High versus low carbohydrate in Skimo race performance: a randomized controlled trial(Montana State University - Bozeman, College of Education, Health & Human Development, 2024) Topf, Rachel Marie; Chairperson, Graduate Committee: Mary P. Miles; This is a manuscript style paper that includes co-authored chapters.Ski mountaineering (skimo) is a high-intensity sport with several race disciplines of varying lengths in which competitors face many challenges that can make consuming food and fluids difficult. There is currently a scarcity of literature on skimo, particularly on nutrition in individual-format races. Exercise >1.5 h, as in an individual skimo race, may benefit from high carbohydrate consumption of > or = 90 g/h compared to lower recommendations of 60 g/h. However, gastrointestinal upset is worsened with increasing amounts of carbohydrate consumption, especially during high-intensity exercise. Highly-branched cyclic dextrin is a glucose polymer with a low osmolality allowing it to have a fast gastric emptying rate which can decrease gastrointestinal upset during exercise. The first purpose of this study was to survey skimo athletes about their nutrition knowledge and practices. With this new information combined with recommendations on carbohydrate and fluid intake, the second purpose of this study was to test an 18% solution of highly-branched cyclic dextrin + fructose (3:1) in a skimo race. It was hypothesized that an 18% solution (90G) would improve performance in an individual race compared to a 6% solution (30G) without contributing to gastrointestinal upset. Fifteen participants completed the randomized controlled crossover trials. Average carbohydrate consumed was 27 and 85 g/h and race time 105 and 107 min in 30G and 90G, respectively. Overall race times were not significantly different. Gastrointestinal upset trended higher in 90G (p=0.07). When the four participants with high gastrointestinal upset (rating >4/10) were removed from analysis, there was a main effect for drink on percent lap time change (p<0.001), with 30G having a greater percent increase in lap time throughout the trial. In conclusion, a high-carbohydrate drink was created to address the needs of skimo athletes. It was found that an 18% carbohydrate solution had significantly higher gastrointestinal upset ratings and did not confer additional performance benefit compared to a 6% solution. Additionally, high gastrointestinal upset with the 18% solution appears to have contributed to slower time; however, those without high gastrointestinal upset with the 18% solution had a lesser percentage change in lap time throughout the trial compared to 6%.Item The influence of high fructose corn syrup on endurance exercise metabolism(Montana State University - Bozeman, College of Education, Health & Human Development, 2014) Rauk, Erika Leigh; Chairperson, Graduate Committee: John G. Seifert; John G. Seifert, Mary P. Miles and Alison H. Harmon were co-authors of the article, 'The influence of high fructose corn syrup ingestion on endurance exercise metabolism' submitted to the journal 'European journal of applied physiology' which is contained within this thesis.Athletes are advised to ingest adequate amounts of carbohydrate (CHO) prior to competitions, during exercise, and after to replenish glycogen storages. Performance outcomes can be determined by the amount, timing, and sources of CHO ingested. High fructose corn syrup (HFCS) is thought to be one of the main contributors in the development of obesity and chronic disease, therefore making this CHO source controversial. The study purpose was to determine if a HFCS-sweetened beverage is an acceptable CHO source for prolonged moderate intensity exercise by determining its effects on substrate metabolism during exercise when compared to a dextrose-sweetened beverage (DEXT). Eleven (6 male, 8 female: Mean±SD; 24 ± 3.9 yrs, 71.8 ± 12.5 kg, 173.8 ± 9.5 cm) active healthy adults volunteered to participate in for this study. A baseline blood sample was drawn prior to ingesting half of a 400 mL beverage sweetened with 50 grams of HFCS or DEXT 15 min prior to a 120 min cycle and the other half was consumed 10 min of exercise. This was a randomized, double-blinded study. Blood was collected at -20, 58, and 140 min, tested for glucose, lactate, hemoglobin and hematocrit, then coagulated for 20 min, centrifuged for 10 min for serum separation and analyzed for lipids. Respiratory exchange ratio, HR, and RPE were collected at 20, 50, and 115 min during exercise. Treatment interaction effects were determined using repeated measures ANOVA and a one-way ANOVA, with a Tukey (HSD) post hoc test (alpha level < 0.05). All statistics were mean ± SD. There were no significant time by treatment interactions or main treatment effects for any dependent variable RER (p=0.996), triglycerides (p=0.451), CHOL (p=0.230), LDL (p=0.875), HDL (p=0.753), VLDL (p=0.439), glucose (p=0.802), HR (p=0.749), RPE (p=0.719), or lactate (p=0.065). However, there was a significant time effect identified for decreasing RER, increasing HR and RPE that were not related to the treatments, but the physical needs of exercise. In conclusion, the current study demonstrates an acute 50 g dose of HFCS at the beginning of prolonged moderate intensity exercise does not induce hypertriglyceridemia and is an adequate CHO source for supplementation.Item The effects of carbohydrate on inflammation following an acute bout of resistance exercise(Montana State University - Bozeman, College of Education, Health & Human Development, 2006) Pearson, Sherri Diane; Chairperson, Graduate Committee: Mary P. Miles.The immune response to inflammation involves the release of cytokines, which determine the intensity and duration of the immune response (Kuby, 1997). The cytokine interleukin-6 (IL-6), functions as a negative feedback signal that turns off pro-inflammatory mediators during the immune response. IL-6 also initiates the release of CRP, which induces inflammation. Therefore, IL-6 is known as both a pro and anti-inflammatory mediator of the immune response. IL-6 is released during the immune response to inflammation. IL-6 peaks about 8 hours after an eccentric exercise session that induces muscle damage. Carbohydrate ingestion during endurance exercise attenuates the rise in IL-6 immediately post-exercise during recovery. IL-6 along with the acute phase protein C-reactive protein (CRP) (a marker of the systemic inflammatory response), and creatine kinase (CK) (a semi-quantitative marker of muscle damage), will be used to determine the affects of eccentric exercise on muscle damage and the inflammatory response.Item Do carbohydrates increase the magnitude of the inflammatory response(Montana State University - Bozeman, College of Education, Health & Human Development, 2008) Depner, Chris M.; Chairperson, Graduate Committee: Mary P. Miles.Inflammation is the body's response to tissue damage and infection and is correlated with several chronic diseases like type II diabetes. Cytokines are cell signaling proteins with multiple functions including control of inflammation. Cytokines are influenced by several factors such as carbohydrate intake and exercise. Thus, carbohydrate intake and exercise can influence inflammation. Purpose: To determine the influence of high carbohydrate intake on the inflammatory response to exercise that induces muscle damage and inflammation. Methods: The study was a cross-over design. Each subject completed a high carbohydrate condition and a high fat and protein condition. Each condition consisted of 6 sets of 10 maximal high-force eccentric contractions of the elbow flexors and extensors. The exercise was followed by a controlled diet for the first 8 hours post-exercise based on the condition. The cytokines interleukin-6 (IL-6) and interleukin-1B (IL-B) were measured as indicators of local inflammation. C-reactive protein (CRP) was measured as an indicator of systemic inflammation. Creatine-kinase (CK), muscle soreness, upper arm circumference, and strength loss were measured as indicators of muscle damage. Blood glucose and insulin were measured to identify differences between diets in the conditions. Results: Insulin was significantly increased in the high carbohydrate condition compared to the high fat and protein condition at 1.5, 4, and 8 hours post-exercise. Perceived soreness was elevated at all time points post-exercise in both conditions and was significantly elevated in the high carbohydrate condition compared to the high fat and protein condition. There was a main effect trend for IL-6 to be greater in the high carbohydrate condition compared to the high fat and protein condition. Il-1B was significantly increased 24 hours post-exercise in the high carbohydrate condition compared to the high fat and protein condition. Conclusion: Elevated carbohydrate intake post-exercise augmented the local inflammatory response to the exercise observed by elevated IL-1B and IL-6. The augmented inflammatory response contributed to greater perceived muscle soreness post-exercise. Further research is required to investigate this mechanism further to provide better prevention and treatment methods for chronic diseases related to inflammation.