Training and the Brain
Exercise: It’s for cognitive and psychological gains too!
By Courtney Kelly
Overview
Total Read Time: 8 - 12 Minutes
1. Introduction (2 - 3 minute read)
2. Exercise and Cognition (2 - 3 minute read) How exercise can help improve the cognitive performance of individuals at all stages of life, including those with neurodevelopmental or neurodegenerative conditions.
3. Exercise and Psychological Health (1 - 2 minute read) How exercise benefits mental health.
4. Exercise and Neurobiology (2 - 3 minute read) The physical changes that exercise elicits in the brain to promote cognitive and psychological benefits.
5. Some Final Thoughts (1 minute read) A couple of big takeaways.
6. Sources
Part I: Introduction
Humans aren’t the fastest. Or the strongest. We’re not the longest living, and we’re definitely not the toughest. In a competition awarding superlatives to worthy members of the animal kingdom, we’d go home largely empty-handed. Except, perhaps, in one category (if whales don’t end up edging us out out at the buzzer): Intelligence.
Our brains are the most precious attribute we’ve got. They’ve played a key role in our survival as a species, and without them, we aren’t much more than pliant sacks of comparably wimpy muscle with sweat glands and thumbs. Which is why we’d like to shift our focus away from muscles for a moment and towards that three-pound hunk of neuronal matter thinking around in our noggins.
Before you ditch this post because you came here to learn about physical, not cognitive, performance, stick with us! This article’s still about fitness, and it’s still about exercise. It’s just that we’re going to talk about these things in terms of how they affect our brains, not our muscular-skeletal systems. Because, as it turns out, one of the most important reasons to train may be that it’s good for our minds, not simply because it’s good for our bodies.
Bold statement, I know. But consider this: Across age groups, exercise has shown itself to improve cognition and psychological health. It’s helped middle school students score better on academic standardized tests. It’s helped seniors suffering from neurodegenerative diseases reclaim their memories. And it’s served as a powerful ally for people of all ages in their battles with mental illness.
But how? And why? As with most things that have to do with exercise and sports science (and cognitive science AND psychology, for that matter), we’re still in the early stages of figuring it out. We have some good leads, but there’s a lot of research yet to be done. What we can say for certain is this: Regular exercise can help keep your mind healthy and sharp into old age.
Throughout this article, we’re going to summarize recent scientific research on the relationship between exercise and the mind. We’re also going to outline the neurobiological underpinnings of this relationship -- scientists’ theories about them, anyway. We’re not, however, going to cover every detail and nuance of the way that exercise affects the brain. This article is not meant to be an exhaustive opus on the subject. It’s supposed to raise your awareness, pique your interest, and, perhaps (if you haven’t already), encourage you to take up a movement practice of your own.
Part II: Exercise and Cognition
Before jumping into how exercise benefits cognition, a quick explanation is in order. Cognition refers to the act of carrying out mental tasks. In case you’re interested, the English word, “cognition” comes from the Latin word, “cognosco”, which roughly translates to “I become acquainted with/ I learn.” And the English word still carries around a lot of its Latin trappings.
There are many subcategories of cognition that individuals can choose to study, ranging from executive functioning, which refers to attention and behavior control (among other things), to learning, language processing and production, spatial reasoning, quantitative reasoning, memory, visual processing and…well, the list is long, and it only gets longer the more established the field becomes.
As some recent studies have demonstrated, exercise can improve cognitive performance across subcategories and age groups. For example, acute bouts of exercise have been shown to help young children, middle school students, and young adults perform better on cognitive tests of all kinds: math tests, tests of inhibition control, tests of attention, tests of cognitive flexibility, and tests of mental processing speed, to name a few. Individuals diagnosed with ADD or ADHD, neurodevelopmental conditions characterized by difficulties carrying out a variety of executive functioning tasks, have also been shown to perform better on tests of attention and inhibitory control after acute bouts of exercise.
Important note: “Acute bout of exercise” refers to a single session of physical exertion. In many of the studies informing the paragraph above, this single session of exercise immediately preceded a test of cognitive performance. And that means these studies were testing the effects of exercise-induced physical arousal, not necessarily the effects of consistent exercise performed over time. For that, we have some other studies.
Consistent exercise has been shown to reverse the effects of dementia and Alzheimer’s disease. It’s also been shown to forestall the onset of cognitive decline. According to a meta-analysis entitled, “The potential mechanisms of exercise-induced cognitive protection: A literature review,” an eight-year longitudinal study found that “older adults who were physically active during leisure time had better subsequent cognitive function and a slower rate of cognitive decline than those who were not.”
Consistent exercise performed over time was also shown to improve college students’ memory as it applied to novel object recognition memory tests in a study entitled, Differential Effects of Acute and Regular Physical Exercise on Cognition and Affect,” so it’s not just the elderly who stand become mentally sharper with consistent training. And, for that matter, it’s not just mental “sharpness” that stands to improve with regular exercise, it’s also mental health.
Part III: Exercise and Mental Health
You don’t need us to tell you that depression and anxiety are widespread mental health issues in today’s world. Probably in yesterday’s world, too, but they had different names, like “melancholy” or “hysteria.” And these are far from the only psychological disorders affecting millions of people worldwide. Fortunately, recent scientific research on mental illness has raised more awareness about these conditions and discovered new ways to treat them.
Scientists have found that regular exercise can help elevate mood, lower stress, improve mental resilience, boost self efficacy (belief in one’s own ability to accomplish things), and support increased mental flexibility. And all of these effects can serve to ameliorate mental illness. Writes psychologist, Dr. Sarah Gingell in her article, “How Your Mental Health Reaps the Benefits of Exercise,” exercise “appears to be as good as existing pharmacological interventions across a range of conditions, such as mild to moderate depression, dementia, and anxiety, and even reduces cognitive issues in schizophrenia.”
In fact, as Dr. Gingell explains, “Three or more sessions per week of aerobic exercise or resistance training, for 45 to 60 minutes per session, can help treat even chronic depression. Effects tend to be noticed after about four weeks, and training should be continued for 10-12 weeks for the greatest anti-depressant effect.”
With side effects that include things like improved cardiovascular health, improved metabolic efficiency, and increased muscle mass, exercise presents as a pretty appealing component to any mental health treatment program.
“But!” you may be wisely interjecting, “How can we know exercise itself is catalyzing mental health improvement, not just the social components of group exercise?”
We’re so glad you asked! While the benefits conferred by the social aspects of training cannot be overstated, there is evidence that regular exercise itself catalyzes biological changes which support improved mental health. These biological changes, as it happens, are thought to be the same mediums through which exercise improves cognition. More about them below!
Part IV: Exercise and Neurobiology
Throughout this article, we’ve been discussing exercise in general, but here, it’s helpful to differentiate between resistance training and aerobic training. This is because scientists have recently found that these two broad categories of exercise seem to elicit slightly different neurobiological responses.
The effects of resistance training on the brain are just beginning to be understood by scientists, as much of exercise and sports science research has been focused on aerobic exercise until recently. A meta-analysis published this year, entitled, “Functional and/or Structural Brain Changes in Response to Resistance Exercises and Resistance Training Lead to Cognitive Improvements -- a Systematic Review,” cross-examined 18 research papers on resistance training and cognition. According to this meta-analysis, “Resistance exercises and resistance training evoked substantial functional brain changes, especially in the frontal lobe, which were accompanied by improvements in executive functions. Furthermore, resistance training led to lower white matter atrophy and smaller white matter lesion volumes.”
This is significant because “white matter,” which consists primarily of myelinated axons, is critical for the transmission of information among brain regions. And because complex cognitive tasks like language production, quantitative reasoning, decision making, and abstract thinking require the coordination of many different parts of the brain, keeping white matter intact is critical for keeping our minds competent and capable.
But it’s not just white matter that’s important to cognition -- far from it! Keeping gray matter intact is also critical to cognitive performance. Gray matter consists of neuronal cell bodies and other, non neural brain matter that includes capillaries and glial cells. It comprises the regions of our brain that not only perform complex cognitive tasks but that also control the performance of physical tasks like locomotion. It’s important stuff.
Excitingly, research shows some evidence that resistance training is good for brain matter of the gray variety too! “The potential mechanisms of exercise-induced cognitive protection: A literature review,” a meta-analysis we referred to earlier, explains that resistance training has also been associated with “structural changes in … gray matter … in the healthy adult brain.”
Scientists theorize that resistance training contributes to the growth of nervous tissue by triggering the release of neurochemicals like brain-derived neurotrophic factor (BDNF), which is both associated with improved cognition and improved mental health.
Aerobic exercise has also been associated with increases in the volume of various brain regions, including the hippocampus. Because of the central role that the hippocampus plays in memory, an increase in hippocampal volume is thought to be a key contributer to improved cognitive function.
According to “The potential mechanisms of exercise-induced cognitive protection: A literature review,” regular aerobic exercise has also been shown to “promote antioxidant capacity in the brain.” This means that regular aerobic exercise can help reduce oxidative stress on the nervous system-- a stress caused by free radicals.
You can think of free radicals as outcasts that rove around in bodies hunting for molecules they can pilfer electrons from. And when they steal electrons, they change the chemical makeup of molecules, which can be good if those molecules are associated with pathogens, but bad if those molecules are associated with a body’s cells. If free radicals take electrons from the a body’s cells, they can contribute to tissue degradation on a larger scale. Aerobic exercise helps brains become better at resisting damage from these plundering rogues.
Part V: Some Final Thoughts
Exercise is good for you. It’s good for your body, and it’s good for your mind. We still have a lot to learn about exactly how and why it’s good for the mind, but current scientific research provides strong evidence that exercise benefits both cognition and psychological health. Because it seems that resistance training and aerobic training impact the brain in slightly different ways, combining them under a concurrent training model may be ideal for reaping the cognitive/ psychological benefits of exercise.
As with anything, more isn’t always better. Over-exercising or exercising at too high an intensity too often can be detrimental to both mental and physical health. Giving the body adequate recovery time is critical not only for reaping the maximal psychological and physiological benefits of exercise, but it’s also the key to sustaining your exercise practice over the long term. And you know we’re all about that sustainability.
So! Happy -- and we really mean it -- training!
Sources:
1. Norman, Jennifer E, et al. “The Potential Mechanisms of Exercise-Induced Cognitive Protection: A Literature Review.” Current Pharmaceutical Design, U.S. National Library of Medicine, 2018, www.ncbi.nlm.nih.gov/pmc/articles/PMC6384011/.
2. T., Andrew, et al. “Acute Exercise and Academic Achievement in Middle School Students.” MDPI, Multidisciplinary Digital Publishing Institute, 20 Sept. 2019, www.mdpi.com/1660-4601/16/19/3527/htm.
3. Gingell, Sarah. “How Your Mental Health Reaps the Benefits of Exercise.” Psychology Today, Sussex Publishers, 22 Mar. 2018, www.psychologytoday.com/us/blog/what-works-and-why/201803/how-your-mental-health-reaps-the-benefits-exercise.
4. Christiansen, Lasse, et al. “Effects of Exercise on Cognitive Performance in Children and Adolescents with ADHD: Potential Mechanisms and Evidence-Based Recommendations.” Journal of Clinical Medicine, MDPI, 12 June 2019, www.ncbi.nlm.nih.gov/pmc/articles/PMC6617109/.
5. Herold, Fabian, et al. “Functional and/or Structural Brain Changes in Response to Resistance Exercises and Resistance Training Lead to Cognitive Improvements - a Systematic Review.” European Review of Aging and Physical Activity : Official Journal of the European Group for Research into Elderly and Physical Activity, BioMed Central, 10 July 2019, www.ncbi.nlm.nih.gov/pmc/articles/PMC6617693/.
6. Hopkins, M E, et al. “Differential Effects of Acute and Regular Physical Exercise on Cognition and Affect.” Neuroscience, U.S. National Library of Medicine, 26 July 2012, www.ncbi.nlm.nih.gov/pmc/articles/PMC3374855/.