Your Brain & Exercise

The adult human brain was once understood as being incapable of forming new neurons. The common understanding was, in fact, that the brain began losing neurons. The actual evidence and our understanding now, is that adult brains can form new neurons. Additional evidence has been discovered that establishes exercise has positive effects on human brains, notable as brains age. Exercise may also reduce the risk of Alzheimer’s disease and other neurodegenerative conditions. This evidence prompts a key question: Why does exercise affect the brain?

Physical exercise improves the function of most organ systems in the human body. These benefits are usually linked to better athletic performance. A good example is when you walk or run, your muscles demand more oxygen. Over time your cardiovascular system responds by increasing the size of the heart and building new blood vessels. Enhanced endurance is a byproduct of cardiovascular changes caused by exercise.  How do the cardiovascular changes evoke a change in the brain?

Walking and running was once considered activities that are performed on autopilot.  Recent research indicates that this basic presupposition is false. Exercise, instead, seems to be as much a cognitive activity as a physical one. With this in mind, there is the potential to develop exercise routines that benefit cognitive ability as people age.

To understand why exercise benefits the brain, we need to understand which aspects of the brain structure are most responsive to it. Researchers found that running increases the formation of hippocampal neurons in mice. They noted that this process was tied to the production of a protein called Brain-Derived Neurotrophic Factor (BDNF). Additionally, the research on animals demonstrated that exercise-induced neurogenesis is associated with improved performance on memory-related tasks. These studies are considered important because atrophy of the hippocampus is linked to memory loss during normal human aging, memory loss in people with Alzheimer’s and other neurodegenerative diseases.

Research continued on human subjects. Just like in the previous study, aerobic exercise leads to the production of BDNF in key areas of the brain in humans as well. Multiple research projects came to the same conclusions that people middle-aged to older adults who spent time engaged in moderate to vigorous physical activities had larger hippocampal volumes. While some of the causes may be unknown, the results are clear that exercise can benefit cognitive function in humans.

This article is based on information from:
Scientific America: Why Your Brain Needs Exercise – The evolutionary history of humans explains why physical activity is important for brain health