ALT A decline in ‘our ability to think’ is part of natural ageing and is partly due to deficits in blood flow delivering oxygen and nutrients to the brain. Evidence shows that being physically active improves blood flow to the brain and results in better cognition later in life. We have shown that better cognition can be seen after a single bout of exercise. As such, enhancing exercise-induced changes in brain blood flow has the potential to result in better cognition, and over the longer term optimizing the benefits of physical activity can be a way to improve resilience against cognitive decline later in life. Critically, there is evidence showing that individuals with low levels of fitness have lower increases in brain blood flow when engaging in moderate/high-intensity physical activity when compared to high-fit individuals, and this is also linked to poorer cognition.