It spurs brain growth
As we get older, the birth of new brain cells slows, and our brain tissue actually shrinks. Exercise may be able to reverse that trend. One brain-scanning study of healthy but sedentary people aged 60 to 79 showed significant increases in brain volume after six months of aerobic fitness training. No such changes occurred among controls who only did stretching and toning exercises. The researchers concluded that the improved cardiovascular fitness that comes with aerobic exercise is associated with fewer age-related changes in the brains of older people. Cardio boosts blood flow to the brain, which delivers much-needed oxygen (the brain soaks up 20 percent of all the oxygen in your body
It boosts brain-building hormones
Much like plant food makes plants grow faster and lusher, the chemical known as brain-derived neurotrophic factor, or BDNF, stimulates the growth and proliferation of brain cells. This is especially true in the hippocampus, the brain region that is largely responsible for memory and which is particularly vulnerable to age-related decline. The more you exercise, the more BDNF you produce.
It fights depression and anxiety
Depression slows the brain’s ability to process information, makes it more difficult for us to concentrate and reach decisions, and causes real memory problems. For serious depression, your doctor may prescribe antidepressants. For milder cases, exercise may help lift your mood. It cranks up the body’s production of serotonin and dopamine, brain chemicals crucial to happy mood. And it boosts levels of the feel-good chemicals called endorphins.
It reduces the effects of stress
If some hormones like BDNF make the brain younger, others help age it. These include the so-called stress hormone cortisol. Slow, scattered thinking and forgetfulness are caused by stress more often than we may realize. Exercise lowers cortisol levels, helping you to think straight again. It is also believed to help generate new nerve cells in the area of the brain called the dentate gyrus, an area of the hippocampus linked to the creation of new memories. Brain cells here are depleted during times of stress.