Biological Mechanisms of Fitness on Brain

High aerobic fitness correlates with larger hippocampal, basal ganglia, and prefrontal cortex volumes, enhanced white matter integrity, and more efficient brain activity patterns. Exercise triggers the release of myokines including BDNF, IL-6, IGF-1, and cathepsin B that cross the blood-brain barrier and promote neurogenesis and synaptic plasticity. Physical fitness is associated with elevated cerebral blood volume, which itself stimulates neurogenesis. Aerobic and resistance exercise slow musculoskeletal ageing and improve skeletal muscle function through brain-muscle cross-talk, a mechanism considered particularly relevant to the hand grip-cognition association in males. Sex hormones including leptin and oestrogen located within adipose tissue may modulate cognitive decline in ways that differ between males and females.