Jennah Brown Rose Hills
The Regulation of Metabolic Flexibility in Aging
Mitochondrial function and metabolic flexibility (the ability to switch back and forth between carbohydrate and lipid utilization in response to changing physiological conditions) degrade as a normal consequence of aging. Metabolic flexibility is regulated by several mechanisms that are affected by the capacity for lactate oxidation and, therefore, mitochondrial function. Previous studies have demonstrated that endurance training improves metabolic flexibility due to improvements in mitochondrial function and the capacity for lactate oxidation. The purpose of my research is to assess metabolic flexibility in older and younger, trained and untrained individuals by measuring blood lactate and substrate oxidation rates during postabsorptive rest. I will implement a resting oral glucose tolerance test (OGTT) to analyze how blood lactate concentration interplays with carbohydrate and fatty acid oxidation rates as determined by gas exchange measurements. This method deviates from current methods of metabolic flexibility assessment by proposing a simpler and less invasive approach that may be advantageous for special populations, including those with metabolic diseases. After completing this project, I will continue working with the Brooks Lab to learn direct methods of studying metabolic flexibility.