The Metabolic Effects of β-hydroxybutyrate on Working Skeletal Muscle

The goal of this clinical trial is to test ketone bodies in healthy elderly and young individuals. The main question it aims to answer are: • Do ketone bodies improve skeletal muscle function? Participants will ingest a ketone monoester and skeletal muscle function will then be evaluated by: * Special magnetic imaging techniques * Intravenous infusion of tracer-marked nutrients * Performance tests on a ergometer bike and in a dynamometer Researchers will compare the outcomes between within the young and elderly groups and between the young and the elderly group to investigate if age has an effect on the outcomes.