You can’t fix what isn’t broken: eight weeks of exercise do not substantially change cognitive function and biochemical markers in young and healthy adults

Objective The benefits of exercise on brain health is well known in aging and psychiatric populations. However, the relationship between habitual exercise in young and healthy adults remains unclear. This study explored the effects an eight-week exercise prescription on cognitive function, brain-derived neurotrophic factor (BDNF) and cathepsin B (CTHB) in young and healthy adults. Methods A total of 22 low-active, young and healthy adults were recruited from a local university. A total of 12 participants performed an eight-week exercise prescription and 12 participants served as controls. Cognitive assessments, cardiorespiratory fitness and plasma BDNF and CTHB concentrations were measured at baseline and eight weeks. Results Results showed exercise improved cardiorespiratory fitness ( p = 0.044, d = 1.48) with no improvements in cognitive function or no changes in plasma BDNF and CTHB concentrations. Conclusion We provide evidence that a short-term course of moderate exercise does not improve cognitive function or change plasma biochemical markers concentrations in young and healthy adults, despite mild improvements in cardiorespiratory fitness. These results suggest that cognitive health may peak during early adulthood leaving little room for improvement throughout this period of the lifespan.