Aerobic Exercise in the Fasted State: The Effects on Aerobic Capacity in Healthy Adults

There are numerous variables that can affect energy metabolism during aerobic exercise and possibly play a role in the increase of aerobic capacity. Dependence on fat oxidation such a factor and approaches are sought to maximise adaptations in enhancing this metabolic switch. A strategy that has been explored increasingly is the dietary pattern of the fasted state. With aerobic exercise and the fasted state relying on complimentary energy metabolism pathways, this literature review aimed to investigate a pivotal interaction between aerobic exercise in the fasted state and possible benefits for aerobic capacity. The hypothesis, ‘aerobic exercise in the fasted state will enhance aerobic capacity in healthy adults’, was tested through exploration of implications for aerobic capacity with aerobic exercise in the fasted state. A review of the relevant literature since 2005 relating to the healthy adult population was undertaken, resulting in the critical appraisal of 41 articles. The findings from this review support metabolic switching in fasted state aerobic exercise, demonstrating preferential reliance on fat oxidation, enhanced glucose metabolism and mitochondrial activity. There appear to be benefits that can be derived for aerobic capacity, but further research is warranted to attain greater definition of the effect with fasted state aerobic exercise.