Brain Blood Flow and Lactate in Non-obese and Obese Subjects

Cerebral blood flow (CBF) is essential for maintaining brain health and function, as it ensures delivery oxygen and nutrients necessary to support neuronal activity. Reduced CBF can impair the brain's ability to meet its metabolic demands, leading to deficits in cognitive ability. Impairments in CBF are associated with cognitive decline and neurodegenerative disease such as Alzheimer's and dementia. Many factors influence CBF, but recently lactate has emerged as a key player. Blood glucose has long been considered the primary fuel for the brain, but emerging evidence indicates that lactate may be the preferred fuel for neurons, and lactate may become even more important under stressful conditions. Individuals with obesity often have impaired lactate metabolism resulting in higher resting blood lactate concentrations and reduced ability to clear lactate after a physiological stress. At the same time, it is known that exercise is a powerful intervention for improving lactate metabolism. Thus, this project seeks to investigate the role of lactate in brain blood flow in individuals with and without obesity as well as establish if short term exercise training (individuals with obesity only) will alter circulating lactate concentrations at rest and in response to exercise.