How Exercise Makes Your Brain Bigger, Better, and Stronger

Doctors long have recommended that you get off your couch and exercise if you want to reduce the risk of common physical troubles, such as poor balance or back pain. Now, though, experts are gathering new data on how working out affects your brain, and it turns out that heading to the gym or popping in a fitness video holds significant promise for a building and maintaining a better-functioning noodle.

Hormones and genetics.

Exercise has a big influence on hormonal production within the body. It boosts the creation of substances such as serotonin, dopamine and norepinephrine, for example. These chemicals can improve your mood, and they positively affect areas like perception, arousal, motivation and attention. At the same time, exercise reduces levels of other hormones, such as cortisol. This hormone can damage cells in the hippocampus, one of the areas of the brain researchers associate primarily with memory and learning, so keeping it under control can have a protective result on your cognitive performance.

Hormones also signal your body to create more of a specific protein known as brain-derived neurotrophic factor (BDNF). This protein helps neurons in the brain grow--in fact, scientists have dubbed it "Miracle-Gro for the brain." It also makes the synapses that connect those neurons stronger. Researchers believe this might be in part because ketones, which you produce during exercise as a byproduct of breaking down fat, prevent specific molecules from blocking the activity of the gene associated with BDNF. More specifically, BDNF production seems best with more intense aerobic exercise, particularly in sessions lasting an hour or more. Strength training and similar activities might be beneficial, too, as experts have proved they can boost the speed at which you process information, but the key to BDNF and brain building appears to be ensuring the exercises you choose are hard enough to include a cardiovascular component--that is, they need to elevate your heart rate.

Oxygen, glucose, and insulin.

Getting your sweat on translates to increased blood flow to the brain. Subsequently, brain cells have better access to the oxygen and energy-providing glucose (sugar) they need. Nevertheless, your cells still need a substance called insulin to absorb glucose for fuel. If you become resistant to insulin, which can happen because of habitual overconsumption of sugary foods, your cells no longer can get sufficient amounts of energy, and blood sugar levels can skyrocket. Insulin also plays a part in keeping the connections between brain cells strong. Thus, insulin resistance can mean you can't process or remember information as well. Exercise, however, reduces insulin resistance: If you exercise long and hard enough, you use up the glucose stored in your muscles. The body reacts by making the muscles respond better to insulin so they can take glucose out of the bloodstream and replenish their energy stores.