During the normal aging process, humans inevitably undergo cognitive decline—the experience of more frequent memory loss, confusion, and trouble learning and concentrating. Not surprisingly, research shows that participating in brain-stimulating activities, such as puzzles or math problems, can help keep our brains healthy for as long as possible.
But research also shows something unexpected: physical exercise is also imperative to prevent cognitive decline. It turns out that if you're worried about your brain health, it is just as important to hit the weights as it is to hit the books.
It is a myth that your brain grows only during the critical periods of development in early life. It is always adapting to best fit an individual's surroundings. The inherent property of the adult brain that enables the nervous system to modify its organization in response to learning, new experiences, or changes in an organism's environment is called neuroplasticity.
Exercise-induced changes in neuroplasticity are thought to play a critical role in producing the beneficial effects that are associated with physical activity, including improved memory, cognitive functions, and neuroprotection—the preservation of neuronal structure and function.
How so?
Many studies have been done to elucidate the pathway by which the cognitive benefits emerge.
Physical activity is correlated with increased cerebral blood volume, a measure of brain health, and improved VO2 max, an indicator of cardiovascular fitness and aerobic level. Those with higher VO2 maxes showed greater changes in blood oxygenation and increased blood circulation in the brain. Physical activity also promotes angiogenesis, which is the development of new blood vessels in the brain. A combination of these factors allows for more efficient bloodstream delivery of nerve cell regulators, proteins, and supporting factors to critical brain areas [1].
Additionally, several neurotrophins, proteins that regulate the development, maintenance, and function of nervous systems, are positively affected by physical activity. Studies showed that brain-derived neurotrophic factor (BDNF) appears elevated in the rat and mouse hippocampus after long-term exercise [2]. Other studies proved cAMP response element-binding protein (CREB) levels increased in mice after 5 weeks of exercise. These neurotrophins are important regulators for nerve cells and are known to have a significant role in neuroplasticity [3].
Repeated exercise improves cerebral oxygenation and circulation, elevating the levels of these neurotrophins by improving delivery to parts of the brain, ultimately yielding increased cognitive performance in spatial memory and recognition tasks, and on a wider scale, a greater capacity for neuroplasticity.
This is just one pathway by which physical activity brings about cognitive benefits. Multiple pathways exist. And numerous studies have shown similar outcomes.
One study reported physical exercise at age 36 was associated with a slower rate of memory decline between 43 and 53 years of age. The study also demonstrated that participants who engaged in physical exercise at the age of 36 through 43 had the lowest decay in memory at age 53 [4]. Other structural brain imaging studies demonstrated that gray matter volume in frontal brain regions, a measure of brain health, was found to be larger for individuals who had reported exercising at least twice a week compared to those who exercised much less or none at all [5].
It’s important to note that for physical activity to be effective in promoting these cognitive benefits, it must be repeated on a long-term scale. One half-mile run will certainly release endorphins, possibly boost your confidence, and leave you feeling quite energetic and happy, but those feelings will soon fade.
Lastly, one more thing to consider: a broad section of currently available literature supports the idea that physical activity will yield cognitive benefits most effectively when done in combination with cognitive training which activates some task-dependent regions in the brain [6]. To fully maximize the benefits of physical activity, research shows that hitting the gym and the library in combination could be helpful.
No matter what stage of life you are currently in—middle schooler, retired citizen, or something in between—it is crucial for you to begin exercising. Physical activity is one of the few things that has been scientifically proven to boost your brain health. Start small, build your endurance and strength, and gradually increase intensity and duration. Although the most obvious benefits of exercise, including strengthening muscles and weight management, are not to be understated, the most exciting advantage is being able to delay the deterioration of our cognitive abilities.
[1] Stimpson, Nikolas J., Glen Davison, and Amir-Homayoun Javadi. “Joggin’ the Noggin: Towards a Physiological Understanding of Exercise-Induced Cognitive Benefits.” Neuroscience & Biobehavioral Reviews 88 (2018): 177–86. https://doi.org/10.1016/j.neubiorev.2018.03.018.
[2] Ibid.
[3] Ibid.
[4] Hötting, Kirsten, and Brigitte Röder. “Beneficial Effects of Physical Exercise on Neuroplasticity and Cognition.” Neuroscience & Biobehavioral Reviews 37, no. 9 (2013): 2243–57. https://doi.org/10.1016/j.neubiorev.2013.04.005.
[5] Richards, Marcus, Rebecca Hardy, and Michael E.J Wadsworth. “Does Active Leisure Protect Cognition? Evidence from a National Birth Cohort.” Social Science & Medicine 56, no. 4 (2003): 785–92. https://doi.org/10.1016/s0277-9536(02)00075-8.
[6] Barnes, Deborah E. “F4-01-04: The Mental Activity and Exercise (MAX) Trial: A Randomized, Controlled Trial to Enhance Cognitive Function in Older Adults with Cognitive Complaints.” Alzheimer's & Dementia 6 (2010). https://doi.org/10.1016/j.jalz.2010.05.449.