Aerobic exercise of 30 minutes duration, 3-4 times per week has been found to enhance plasticity by increasing the volume of the hippocampus and prefrontal cortex (PFC). The impact of the enhanced hippocampus is better memory, whilst for the PFC, attention function has been found to improve (among other things). Wendy Suzuki mentions that research shows the hippocampus and PFC are parts of the brain which are most susceptible to neurodegeneration and aging. Exercise has also been shown to increase levels of favorable neurotransmitters in the brain. This includes dopamine, noradrenaline and serotonin, and explains why we feel good after exercise (especially if we didn’t feel like exercising 30 minutes before that!).
In addition to the effects noted above, exercise assists in protecting us against the effects of neurodegenerative diseases such as Alzheimer’s. This may be because there is greater reserve in the brain for those who have exercised their brains through, for example, neurogenesis.
For most beneficial effects, it would be wise to consider your specific exercise needs based partly on your genetic history, lifestyle and current age. Remember not to do anything your doctor would not want you to do!