How Exercise Helps The Brain – From Brain Health To Cognitive Performance
Learn how exercise helps the brain, from reduced inflammation, slowed brain aging, and improved cognitive performance.
© 2025 Modern Mind Masters - All Rights Reserved
Exercise — we love to hate it, but we know it’s non-negotiable. It keeps the extra pounds at bay, our muscles strong and functional, and our hearts happily pumping away — instead of unexpectedly calling it quits.
Yet few, even with today’s wealth of knowledge, truly understand just how essential exercise is to every aspect of health, especially the brain. While many view it as a supplement to health, exercise, and more specifically physical activity (i.e. movement), actually defines our physiology and our health.
Most in the Western World live at the opposite of a strong physical activity routine – being sedentary. Whether sitting in front of the couch, driving to and from (or for) work, or sitting in front of a computer screen for most of the day, the damage of a sedentary lifestyle is even worse than we think.
This article will overview the importance of physical activity, such as exercise, on brain health and its ability to perform functionally and at its peak, as well as the detriments of a sedentary lifestyle to brain health and cognition.
More importantly, we will also explain what a strong physical activity regimen looks like (hint, an hour of gym once a day does not constitute a physically active lifestyle), and what sort of health and performance benefits you can expect from adopting an active lifestyle.
The goal is to shift our perspective on physical activity—from seeing it as just a health booster to recognizing it as a powerful form of medicine. If that sounds too good to be true, read on.
Before we delve into the details, it’s vital to understand that our brains didn’t just grow by chance—physical activity played a huge role in shaping human evolution.
Our ancestors didn’t have the luxury of sitting around all day. They had to run from predators, track animals, and travel long distances in search of food. Survival, through movements such as hunting or fleeing, depended on one’s ability to move, and, over time, natural selection favored those with bodies and brains wired for physical endurance, coordination, and quick thinking.
The ability to detect dangers and locate food was crucial for survival in early human evolution. This is likely why physical activity triggers the release of a wide range of hormones and chemical messengers that help the body and brain respond effectively to movement.
For example, adrenaline and cortisol are released during exercise to enhance alertness and energy availability, preparing the body for action. At the same time, dopamine, serotonin, and endorphins help regulate mood, reduce stress, and promote well-being. These biochemical responses not only supported survival in ancient environments but continue to play a key role in modern health and mental well-being.
This constant demand for movement didn’t just make humans stronger—it actually influenced how our brains developed. Exercise enhances cardiovascular health, strengthens muscles, and optimizes energy metabolism, but it also fine-tunes our brain for better spatial awareness, problem-solving, and reaction time. In other words, our physiology and brainpower evolved hand in hand with physical activity.
Fast forward to today, and we’re only just beginning to understand how a sedentary lifestyle can wreck our health. The modern world has made movement optional, but our bodies and brains still rely on it. The good news? Physical activity isn’t just about staying fit—it’s a powerful tool for keeping both body and mind sharp, just as nature intended.
The brain and body are intrinsically linked, such that any impact on the health of the body also affects the brain, at least to a moderate degree. Yet when we convince ourselves to go to the gym to keep our hearts healthy, we don’t tend to think much about keeping our brains healthy. Yet this is the exact scenario we face.
For example, the brain depends on a steady supply of oxygen and nutrients, which are delivered through the bloodstream. Regular exercise improves circulation, helping keep the brain well-nourished.
Poor cardiovascular health (from inactivity), on the other hand, reduces the amount of oxygen able to be delivered to the brain, not only reducing its ability to perform, but also increasing the risk of stroke, dementia, and, eventually, cognitive decline.
Thus, society needs to begin to change its view of exercise away from physical health toward acting as a powerful medicine for overall health, physically and mentally.
Fortunately, recent improvements in brain imaging techniques have allowed us to measure the relationship between physical activity and brain activation.
This study, for example, found that just one hour of aerobic exercise a day at about 60 – 70 percent of maximum heart rate resulted in hippocampal growth of about two percent, in just one year.
In the control group, which only did light daily gymnastics without much effort, the hippocampus shrank by about 1.4% over the same period—an average rate of shrinkage in modern societies, though far from ideal.
Meanwhile, those who engaged in aerobic exercise not only improved their physical fitness but also strengthened their memory and mental resilience compared to the gymnastics group. This shows that moderate exercise doesn’t just prevent hippocampal shrinkage—it can actually reverse it, even in old age.
Physical activity is incredibly effective at stimulating hippocampal growth, making it one of the best ways to preserve cognitive function and reduce the risk of depression and neurodegenerative diseases like Alzheimer’s.
Neurotrophins, especially Brain-Derived Neurotrophic Factor (BDNF), are like fuel for the brain, playing a crucial role in keeping neurons healthy, adaptable, and resilient. Without them, cognitive function declines, learning becomes harder, and the risk of neurodegenerative diseases increases.
Neurotrophins are a specialized type of protein that supports the growth, survival, and function of neurons (nerve cells) in the brain and nervous system. These proteins play a crucial role in neuroplasticity—the brain’s ability to adapt, learn, and recover from injury.
When you exercise, especially at higher intensities or for longer durations, your body ramps up BDNF production. This process happens in two key ways:
Interestingly, the type of exercise matters. Open-skill sports like badminton, which require quick reactions and adaptability, tend to increase BDNF more than repetitive activities like running.
The increase in BDNF is linked to how hard your cells are working during exercise. The more you exercise—that is, the higher the intensity, the longer you exercise, and the more often you do it—the more BDNF you tend to produce.
As your muscles and other cells use more energy, their powerhouses (mitochondria) ramp up activity and produce more byproducts (like reactive oxygen species). In the brain, BDNF then helps create more mitochondria and supports energy use, which can improve your thinking and memory.
Interestingly, people who are already well-trained show a stronger BDNF response than those who are mostly inactive.
Beyond boosting brain power, exercise also counteracts the harmful effects of stress, which can suppress BDNF production. Just like certain antidepressants, physical activity can reverse these effects, promoting mental resilience.
Both aerobic (endurance) exercise and resistance training trigger the release of growth factors like insulin-like growth factor 1 (IGF-1), which further supports brain function. These benefits don’t just apply to young brains—exercise-driven neuroplasticity can help adults stay sharp, aid recovery from brain injuries, and may have even played a role in human brain evolution.
It is clear that as we age, we tend to slow down cognitively. While with age comes wisdom, where experiences and memories compound into knowledge, it is clear that, like an older computer, the brain’s ability to process information quickly tends to slow with age.
Tasks that once felt effortless—like recalling names or multitasking—may take longer. This is partly due to reduced white matter integrity (nerve fibers that connect different brain regions), which slows communication between different brain regions.
Additionally, the hippocampus, the brain’s memory center, tends to shrink with age for a variety of reasons, making it harder to form and recall new memories.
Fortunately, the brain possesses the remarkable ability for neurogenesis, where new neurons (nerve cells) are created. For a long time, it was believed that adults couldn’t grow new brain cells, but research from the 1960s revealed that new neurons can form in certain areas, including the hippocampus, which is responsible for memory.
The question is how can we maximize our rate of neurogenesis to keep the brain as young as healthy as possible?
Studies have shown that exercise is one such technique. Evidence suggests that physical activity (PA) helps improve brain functions, including memory and attention, in both children and adults. The idea is that exercises or activities that involve muscle movements release factors that support brain growth and effectiveness.
This has been demonstrated at the cellular level in aged mice, where treadmill exercise was found to increase hippocampal neurogenesis.
Exercise can impact the growth, size, and function of astrocytes—special brain cells that help neurons communicate. This, in turn, affects how many connections neurons form and where they are located, which seem to influence learning and memory.
Many studies in the past 20 years have found that physical activity can influence brain health, and lifespan, and even modify genes through epigenetics. This has led to the idea of “epigenetic age” or “DNA methylation age,” which is a way of more accurately measuring biological aging based on changes in DNA.
Exercise can also create an “epigenetic memory,” meaning these genetic changes help shape the brain’s ability to grow, adapt, and function over time. Interestingly, some of these exercise-related genetic changes might even be passed down to future generations.
Science is increasingly looking toward the relationship between the gut microbiome, the trillions of bacteria and other microorganisms living in the digestive tract, and its direct connection and influence on the brain.
Exercise has been shown to increase the diversity and number of beneficial gut bacteria, which helps with digestion, reduces inflammation, and supports overall brain health.
Regular physical activity lowers systemic and gut inflammation, reducing the risk of conditions like IBS, leaky gut, and even neuroinflammation that has been linked to brain function.
The gut and brain communicate through the vagus nerve, and exercise has been shown to stimulate vagus nerve activity, leading to better mood regulation and reduced stress, potentially improving conditions like anxiety and depression while also improving cognitive function.
Exercise also helps balance stress hormones like cortisol, which, if too high, can damage gut bacteria and increase gut permeability (leaky gut). A healthy gut, in turn, produces more serotonin (the “happiness” hormone), improving mood and mental clarity.
While an exciting and popular area of research, research on the gut-brain connection is still in its infancy, so the full mechanisms of action are yet to be discovered.
Mental disorders are at an all-time high, especially in developed nations such as the U.S. and the U.K. An estimated 25% of American women are on antidepressant medication, while 40% of 18-year-olds have a mental health diagnosis.
While the causes of such disorders are complex and influenced by multiple factors, exercise appears to be a powerful tool for reducing symptoms by lowering stress, balancing brain chemistry, and boosting overall well-being.
While widely recognized for its antidepressant effects, the exact mechanisms underlying exercise’s ability to offset these effects remain unclear, although research suggests that both physiological and psychological factors play a role.
Several key hypotheses attempt to explain this relationship, each offering a different perspective on how physical activity influences mental health.
On the physiological side, the thermogenic hypothesis suggests that increased body temperature from exercise may promote relaxation and reduce muscle tension, though research has primarily focused on anxiety rather than depression.
The endorphin hypothesis proposes that exercise triggers the release of β-endorphins, which enhance mood and well-being. However, debate exists over whether endorphins in the bloodstream truly reflect changes in brain chemistry.
The monoamine hypothesis appears to be the most promising, suggesting that exercise increases neurotransmitters like serotonin, dopamine, and norepinephrine—chemicals often depleted in depression. While animal studies support this theory, human research is limited due to challenges in directly measuring brain chemistry changes.
Psychological explanations include the distraction hypothesis, which suggests that exercise shifts attention away from negative thoughts, reducing depressive symptoms. Studies comparing exercise to other distraction methods, such as relaxation or social activities, have shown mixed results.
Finally, the self-efficacy hypothesis argues that exercise helps build confidence and a sense of accomplishment, counteracting the low self-efficacy often seen in depression.
Overall, it is likely that a combination of biological, psychological, and social factors all contribute to exercise’s antidepressant effects. Different mechanisms may be more relevant for different individuals or stages of depression.
Knowledge is only half of the equation. Putting it into practice comprises the other.
Unfortunately, it’s not quite as simple as going to the gym once a day. While certainly better than nothing, there is more to being energetically healthy than periodic exercise.
The largest misconception is confusing exercise with physical activity. Physical activity refers to any movement of the body that requires energy, such as walking, gardening, or doing household chores. Exercise, on the other hand, is a structured and intentional form of physical activity designed to improve fitness, like running, weightlifting, or yoga. While all exercise is physical activity, not all physical activity qualifies as exercise.
This may seem pedantic, but the distinction is important: The studies above all linked brain improvement to physical activity, i.e., movement. You can have an excellent physical movement profile and never exercise. Conversely, you can exercise once a day and have a poor movement pattern, such as going to the gym for one hour a day and then sitting in an office or vehicle for the next 8 hours.
Regular light movement, such as walking for ten minutes every hour, does more to benefit the body and brain than exercising for an hour, and then remaining sedentary for the rest of the day.
While the exact “volume” of exercise needed for maximum health benefits is still debated, there are general guidelines supported by most health and fitness organizations that form a solid starting point.
A commonly recommended baseline is engaging in physical activities that expend about 1000 calories per week, a level of activity acknowledged as the minimum effective dose for noticeable health benefits, with greater energy expenditures offering additional advantages.
However, it’s important to note that any amount of physical activity is better than none. For instance, engaging in moderately intense exercises for at least 40 minutes per week can effectively prevent type 2 diabetes. Similarly, walking more than 2 hours per week has been shown to reduce the risk of premature death in those with this condition.
In cancer prevention, moderate physical activity for about 30–60 minutes daily has shown a significant protective effect against colon and breast cancer. The highest reduction in breast cancer risk is observed in women who perform seven or more hours of moderate-to-vigorous physical activity weekly. For cancer survivors, exercising at a moderate pace for 3–5 hours per week yields the greatest benefits.
The key finding, however, is that while higher levels of physical activity can offer greater health benefits, even modest amounts can make a significant difference, highlighting the importance of incorporating some form of physical activity into daily routines.
My favorite recommendation comes from the book “Outlive” by Peter Attia, MD, who recommends the following:
Point number 2, which involves raising your heart rate above 60% of your maximum, is known as Zone 2 exercise. I incorporate this daily on a treadmill at home, working at an intensity where I can hold a conversation, but requires a bit of effort. Zone 1 is when you’re able to talk comfortably, which is too low for a good workout, while Zone 3 is when talking becomes difficult and you’re struggling to catch your breath, which is too intense. Zone 2 strikes the perfect balance for improving endurance and metabolic health.
Consistent zone 2 exercise is where you get the biggest bang for your buck, as it confers powerful metabolic benefits by stimulating mitochondrial health without excessive strain on the body.
Zone 2 typically feels oddly easy. But the proof is in the research: sustained moderate exercise increases the number of mitochondria, improves glucose uptake, increases the efficiency of your heart, and reduces the risk for nearly every chronic disease.
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Incorporating regular physical activity into your daily life isn’t just about maintaining a healthy body; it’s about safeguarding your brain and mental well-being.
Exercise stimulates the brain’s growth, enhances memory, and boosts mood, offering protection against cognitive decline and mental health disorders. Whether it’s through Zone 2 exercise, aerobic workouts, or resistance training, each form of movement plays a crucial role in maintaining and enhancing brain function.
The key is consistency—physical activity should be viewed not as a supplement, but as a powerful tool to optimize both physical and cognitive health. Your body has evolved in response to the need to move, and so requires movement to maintain its basic functional health. So, make the shift from being sedentary to integrating movement into your routine—your body and mind will thank you for it.
The brain depends on a steady supply of oxygen and nutrients, which are delivered through the bloodstream. Regular exercise improves circulation, helping keep the brain well-nourished.
Beyond boosting brain power, exercise also counteracts the harmful effects of stress, which can suppress BDNF production. Just like certain antidepressants, physical activity can reverse these effects, promoting mental resilience.
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