Exercise and Prolonged Fasting to Improve Brown Adipose Tissue Function in Postmenopausal Women

Type of Study: Clinical Trial Goal: The goal of this clinical trial is to investigate mitochondrial function in interscapular brown adipose tissue (iBAT) in postmenopausal women and determine whether aerobic exercise, prolonged fasting, or their combination can improve iBAT mitochondrial function and whole-body metabolic flexibility. Participant Population/Health Conditions: The study will involve 60 postmenopausal women aged 45-65 years living with overweight or obesity. Main Questions: The main questions this study aims to answer are: * What are the mitochondrial function and cellular characteristics of iBAT in postmenopausal women? * Can aerobic exercise or five-day prolonged fasting improve mitochondrial function in iBAT and whole-body metabolic flexibility? * Does combining aerobic exercise with prolonged fasting produce greater metabolic adaptations than either intervention alone? * Are improvements in metabolic flexibility maintained four weeks after the intervention? Participants Will: Be randomized into one of four groups: control, aerobic exercise, prolonged fasting, or combined aerobic exercise plus prolonged fasting. Follow their assigned intervention for five consecutive days. Undergo metabolic and physiological assessments before and after the intervention and again four weeks later. Provide dorsocervical adipose tissue biopsies and biological samples to investigate mitochondrial function, adipocyte characteristics, and metabolic adaptations. Comparison Group: Researchers will compare the effects of aerobic exercise, prolonged fasting, and their combination with a control condition to determine their effects on iBAT mitochondrial function and whole-body metabolic flexibility.