Exercise of any kind boosts neuroplasticity, which is the ability of the brain to form and reorganize connections between cells, particularly as a response to experience or learning.

Aerobic exercise increases the production of molecules that improve memory and cognitive functioning. It does this by increasing nerve growth and promoting the formation of blood vessels in the brain.

One of the molecules produced is called brain-derived neurotrophic factor (BDNF), which stimulates extension of and sprouting of new dendrites — the branches of nerve cells that facilitate communication with other nerve cells. Because of this capacity, BDNF improves cell interaction throughout the brain.

Studies have also shown that regular physical exercise can actually increase the size of the brain, especially in areas that control thinking and memory. And better yet: It doesn’t take that much work.

Professor Arthur Kramer and neuroscientists at the University of Illinois showed that it’s not necessary for people to become triathletes to boost brain size and cognitive functioning. In their landmark studies, Kramer’s group recruited middle-age and older adults to walk briskly for about 20 minutes each day, or to engage in stretching and toning without aerobic conditioning.

The researchers used brain scans to measure the size of the hippocampus, a memory center located just under the temples. The scans — performed after six months and after one year of training — showed that there was steady growth in the hippocampus in research volunteers who were walking regularly.

By contrast, the control group that engaged only in stretching and toning showed gradual shrinkage of the hippocampal memory center. In fact, people who are over age 55 and sedentary experience a 1 to 2 percent decline in hippocampal volume each year.