Type 1 Diabetes Mellitus; Exercise-related Fuel Metabolism; Intermittent High Intensity Exercise; Fructose Metabolism; Exercise Physiology
Bally Lia, Kempf Patrick, Zueger Thomas, Speck Christian, Pasi Nicola, Ciller Carlos, Feller Katrin, Loher Hannah, Rosset Robin, Wilhelm Matthias, Boesch Chris, Buehler Tania, Dokumaci Ayse S, Tappy Luc, Stettler Christoph (2017), Metabolic Effects of Glucose-Fructose Co-Ingestion Compared to Glucose Alone during Exercise in Type 1 Diabetes., in Nutrients
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Bally Lia, Zueger Thomas, Pasi Nicola, Carlos Ciller, Paganini Daniela, Stettler Christoph (2016), Accuracy of continuous glucose monitoring during differing exercise conditions, in Diabetes Research and Clinical Practice
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Bally Lia, Zueger Thomas, Buehler Tania, Dokumaci Ayse S., Speck Christian, Pasi Nicola, Ciller Carlos, Paganini Daniela, Feller Katrin, Loher Hannah, Rosset Robin, Wilhelm Matthias, Tappy Luc, Boesch Chris, Stettler Christoph (2016), Metabolic and hormonal response to intermittent high-intensity and continuous moderate intensity exercise in individuals with type 1 diabetes: a randomised crossover study, in Diabetologia
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Buehler Tania, Bally Lia, Dokumaci Ayse Sila, Stettler Christoph, Boesch Chris (2016), Methodological and physiological test-retest reliability of 13 C-MRS glycogen measurements in liver and in skeletal muscle of patients with type 1 diabetes and matched healthy controls Test-Retest Reliability of Liver and Muscle Glycogen Determination, in NMR in Biomedicine
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Bally L., Buehler T., Dokumaci A.S., Boesch C., Stettler C. (2015), Hepatic and intramyocellular glycogen stores in adults with type 1 diabetes and healthy controls, in Diabetes Research and Clinical Practice
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Background: While the beneficial effects of physical exercise are well accepted in type 2 diabetes (T2DM), the role of exercise is more complex in type 1 diabetes (T1DM). Although less frequent than T2DM, T1DM is responsible for 5 to 10 percent of diabetic patients, translating into an estimated number of 25,000 to 30,000 patients with T1DM in Switzerland, many of them being physically active. T1DM is characterized by an autoimmune destruction of the pancreatic beta-cells and treatment essentially consists of exogenous insulin application. For these individuals exercise is associated with an increased risk for hypoglycemia due to increased exercise-associated insulin sensitivity. Since rapid adaptation of insulin dosage may be difficult, alternative strategies to improve exercise-associated glucose stability are required. In addition, exercise-related fuel metabolism in individuals with T1DM is still poorly investigated, and a better understanding of these metabolic pathways may help to refine therapeutic recommendations for these patients. Increasing evidence suggests that intermittent high intensity exercise (IHE) by increasing counter-regulatory hormones (eg. glucagon, catecholamines, cortisol, etc) and by providing glucose from endogenous stores (intrahepatic and intramyocellular glycogen) may counter-balance the risk of exercise-associated hypoglycemia. However, previous studies assessing IHE in T1DM were limited by heterogeneous study populations, comparably short exercise protocols, and deficits in standardization procedures. In addition, a comprehensive assessment of fuel metabolism associated with IHE has not been performed so far. As a consequence results were controversial and interpretation as well as clinical applicability was restricted. An alternative strategy to maintain glucose stability during exercise in T1DM may be deduced from recent studies in non-diabetic individuals suggesting that the combined ingestion of fructose and glucose during exercise provides the liver with an increased amount of gluconeogenetic precursors, thereby reducing consumption of endogenous glycogen stores by competitively increased oxidation of lactate. However, studies assessing the impact of fructose ingestion during exercise in T1DM have not been performed so far.Specific Aims: Based on two approaches the present proposal aims at comprehensively assessing exercise-related fuel metabolism in T1DM and investigating novel strategies to stabilize exercise-associated glycemia:Study 1 will assess exercise-related fuel metabolism of two specific IHE protocols (characterized by different baseline intensities - sub-studies 1A and 1B) compared with iso-energetic continuous exercise (CONT). It will be investigated whether IHE increases glucose stability during and after exercise compared with CONT.Study 2 will assess the impact of a carbohydrate supplementation using a defined mixture of glucose and fructose (GLU-FRU) compared with an iso-energetic supplementation with glucose alone (GLU) on exercise-related fuel metabolism. It will be studied whether GLU-FRU contributes to stabilization of glucose levels during and after exercise when compared to an iso-energetic supplementation with GLU alone.Experimental Design: In a standardized setting including continuous glucose monitoring and pre-exercise glycogen loading we will combine kinetic studies using stable isotopes and quantification of intrahepatic and intramyocellular glycogen stores using magnetic resonance spectroscopy. Expected Value: Results will improve our understanding of exercise-associated fuel metabolism in T1DM and will provide clinically applicable strategies for patients with T1DM. Study 1 will clarify if IHE in standardized conditions improves exercise-related glucose stability by defining underlying mechanisms. Study 2 will provide evidence on the effect of a combined ingestion of fructose and glucose on exercise-associated glycemia in T1DM as opposed to glucose alone, thereby broadening our insights into the metabolic role of fructose.