The Neuroscience of Physical Fitness
Mood disorders like depression, anxiety and chronic stress can cripple your daily life, and spell disaster for your health. You or one of your family or friends may be directly affected, like one in five people in the USA, about 20% of the US’ entire population will be diagnosed with a mood disorder over the course of their lives, according to surveys by the National Institute of Mental Health (NIMH).
Many different approaches can help you lead a happier, healthier life - even though these disorders are serious and potentially life-threatening. Cognitive-behavioral therapies with a counsellor plus medication have been standard. A new form of treatment with fewer side-effects which works immediately has delivered promising results recently, though. Exercise has been shown to reduce the effects of depression and anxiety and protect against cognitive decline. It can even improve your ability to handle high-stress events, such as life transitions, physical injury and workplace stress.
First, we need to understand what we’re dealing with when we talk about mood and exercise. The neuroscience of physical fitness is an exciting, rapidly developing research topic that is set to change the way we treat mood disorders.
- The emotional and economic cost of mental health is staggering
- Exercise may be the key to improving mood
- The brain is a bunch of neurons, chemicals, and seahorses
- Mood disorders are serious biological problems
- The Brain is Plastic
- Exercise changes our plastic brain chemistry
- A prescription for exercise may be on the horizon
The emotional and economic cost of mental health is staggering
What do you do when your body is unhealthy? You might take medicine, go to physical therapy, and try any and all remedies to alleviate the pain, depending on the circumstance. Eventually, you will feel better, stop treatment, and go about your life until the next time you’re feeling ill. It’s a simple story, and one that you’re all too familiar with if you’ve ever been to the doctor for any reason at all.
But how about when your brain is “unhealthy”? When we’re depressed, anxious or chronically stressed, especially when pharmaceutical interventions can come with a multitude of unwanted side effects, we have difficulties answering this question.
Mental health professionals are quick to prescribe counseling services, pills, or lifestyle changes, but the issue is not as clear-cut as treatment for physical ailments. Physicians do their best to prescribe effective treatment in line with the current research, but changing mental health may require changing entire lifestyles.
Regardless, mental health issues are on the rise, and they can have devastating effects on your way of life. The National Institute of Mental Health found that over 17.3 million adults in the United States reported experiencing at least one major depressive episode in 2017. The total economic burden of treating major depression was approximately $210.5 billion in 2010, which accounted for days missed at work, reduced productivity and costs related to pharmaceutical treatment. It’s clear that we need substantial, lasting interventions for our emotional and economic sakes.
Exercise may be the key to improving mood
Imagine that amazing feeling you get after a hard workout. It’s a great feeling, one that keeps you going back to the gym throughout the week. Your breathing is easier and your body is light; it also feels like your mood has improved. The problems that followed you into the gym, or on your run, now seem a distant memory.
Even if you’ve never seriously trained, you can benefit from exercise’s mood-boosting properties. The immediate effects you feel are the result of endorphins in your brain. (These chemicals in our brains cause feelings of euphoria in the short term.) But the long-term benefits of improved mood come from physiological changes in the outer layer of your brain, the cerebral cortex. This is because your brain is undergoing significant molecular and structural alterations as a result of your exercise routine. These neurobiological developments signal the newest frontier for treating depression, anxiety, and stress.
Neuroscientists have studied the role of exercise on improving mood since the turn of the century. Yet, the jury was still out on exercise’s effectiveness in the long-term, especially in the aging brain. The literature largely focused on exercise’s role in our heart health - only scratching the surface of exercise’s role in helping our bodies live life to the fullest.
Recent clinical studies have found that exercise can have immediate - and lasting - effects on our brains. Neuroscientists today are designing a “prescription” for exercise meant to work together with pills, tailored to your specific activity level and age group. This leaves us with a few questions about incorporating exercise into our lives:
- What’s happening to my brain when I exercise?
- Are these mood changes immediate and permanent?
- Can I reap the benefits of exercise at any age?
Current research into the neuroscience of exercise shows physical activity can not only invigorate your muscles, but also change your brain chemistry in permanent ways. Exercise shows promising effects on mood, attention and memory. Your physical exertion results in impactful changes to your neuroanatomy. We’ll show you how we use this information to develop your own personal exercise routine - maximizing the mood-boosting advantages of physical activity.
The brain is a bunch of neurons, chemicals, and seahorses
Our brains are powerful supercomputers that are governed by neurons, synapses and neurotransmitters. We have over 100 billion neurons in our brains, alone. Neurons are cells that have three components: a cell body, axons and dendrites; axons emit signals, while dendrites receive them.
Neurons communicate with one another using electrochemical signals. Our neurons emit electric “spikes” allowing the transfer of chemicals (called neurotransmitters) between the axon of one neuron, and the dendrite of another. The space between a communicating dendrite and axon is known as the synapse. That’s right, our neurons don’t touch each other. (With a few exceptions, but we won’t go down that rabbit hole in this article.)
Your entire brain and behaviors are controlled by the efficiency of your neurons to communicate with one another. Damage to this delicate framework is the root cause of many mental health disorders. This damage can be the result of physical trauma or errors in the communication of our neurotransmitters. Too much or too little of a neurotransmitter can spell disaster for your brain.
The relationship between exercise, mood and neuroscience is complex. You’ll need to understand how our brains are broken down into distinct chemicals and functional areas.
Neurotransmitters most influenced by exercise:
- Dopamine - the pleasure chemical, associated with learning and euphoria.
- Serotonin - the content chemical, associated with feelings of well-being and memory.
- Glutamate - plays a role in learning, memory and plasticity (more on this later!).
- GABA - plays a role in emotional processing.
Brain areas most changed by exercise:
- Hippocampus - long-term memory; exists across both sides of the brain and looks like a seahorse.
- Amygdala - emotional memory system, and impairment of the amygdala correlates with heightened feelings of anxiety and fear.
- Frontal cortex - the front-most part of our brain, associated with personality, decision-making, and thought.
Mood disorders are serious biological problems
Would you tell a cancer patient to “get over it”? Probably not, and the same should go for depressed, anxious and chronically stressed individuals. This struggle is as much a serious biological illness as it is a psychological one. It deserves the same quality of medical attention as any other disease.
Major depressive disorder (MDD) is defined by a persistent low mood uncharacteristic of the individual and lasting at least two weeks. While you can probably relate to feelings of sadness and low mood, MDD is very different from just sadness. If you have felt extremely fatigued, lost interest in your hobbies, were hypersensitive to stress and chronically unfocused, you may have experienced a depressive episode. Suicidal thoughts coincide with severe depressive episodes.
Suicide following depression is the leading cause of preventable death among 15- to 29-year-olds, according to the World Health Organization (WHO) . Researchers at the University of California, Irvine’s Center for the Neurobiology of Learning and Memory found depressed individuals performed significantly worse on tests of working memory. This highlights the impact depression has on multiple aspects of thinking.
Anxiety disorders refer to a group of clinically significant symptoms causing prolonged feelings of panic, dread or phobia. Anxiety is thought to be the most common psychiatric ailment facing human beings. An estimated 13.3% of individuals in the United States are being diagnosed with some form of generalized anxiety, according to studies.
Chronic stress is a bit trickier to define. It’s important to distinguish between necessary stress that we use to solve problems and chronic and debilitating stress which interferes with our ability to function in the world. If you’re stressed for a prolonged period of time, your memory, attention and mood take a massive nosedive.
Commonly thought of only as psychological ailments, depression, anxiety and chronic stress are neurological diseases. They change the brains of sufferers. Remember those neurotransmitters we introduced earlier? They play a role in each of these disorders. Depression is thought to be related to errors in dopamine and serotonin production: too little serotonin in the synapse can lead to depressive symptoms, for example. Anxiety and stress are related to errors in the most common neurotransmitters affecting mood and nervous system health (glutamate and GABA).
When these crucial chemicals function incorrectly, they change our behavior in significant ways - reduced dopamine and serotonin equals less feelings of pleasure; reduced GABA in the synapse can lead to anxiety and low mood. Our cognition is one great balancing act between lifestyle, neuroanatomy and neurotransmitters. Thankfully, though, the laws that allow our brains to change for the worse are also the key to changing our brains for the better.
The Brain is Plastic
Depressed, anxious and stressed people’s brains look different from typical brains. White matter looks substantially different in individuals with mood disorders, according to studies. White matter are the “connector cables” of neurons that allowing signals to brain cells to communicate efficiently.
Malformed white matter weakens the efficiency of our brain areas to talk to each other. This results in debilitating symptoms. It’s similar to how a computer system works. When the wires are faulty, worn down or ripped apart, the entire system is affected.. White matter tracts are exactly like these cables, and even minor malformations can affect your ability to function normally.
Essentially, mood disorders are the result of a biological change in the brain. But that’s just it: Our brains can change. Functionally, your brain has the ability to adapt and transform in substantial ways - not only negatively. Our brains can change for the better.This adaptability has allowed us as a species to thrive in the face of adversity. It’s called “plasticity.”
The word “plastic” stands for neuroplasticity. It refers to the way in which our brains change (not Tupperware or drinking straws). Plasticity is a unique quality of our nervous system. Its role in learning and behavior is still being studied. The extraordinary part is that all brains, regardless of age, are capable of being “plastic.” You’re actually engaging in neuroplasticity right now by reading this very article!
Every time we learn something new, the connections between our neurons are altered. It’s how we’re able to learn anything at all. As you repeat a learned skill, the connections between these groups of neurons get stronger and stronger. You can actually see how strong these connections are when you look at the white matter distributed throughout the brain using functional imaging. It’s our brains’ inherent ability to adapt in this way that makes exercise such a powerful cure.
Exercise changes our plastic brain chemistry
Small amounts of exercise improve mood immediately afterwards, according to the literature on the effect of exercise on the mind. A 2017 review of studies explained that the long-term influence of exercise was unclear, but brief bouts of moderate aerobic exercise improved decision-making capabilities. The reviewers concluded that this was due to the increased blood flow to the frontal cortex. Brief bouts of exercise were also associated with decreased depression, anger and confusion.
Exercise speeds up the creation of new cells in the hippocampus - crucial for memory storage. Daily physical exercise also increases the volume of the frontal cortex, a brain area associated with mood regulation . These changes are robust and permanent - no matter what age. Studies examining exercise and neurobiology found adults of any age can reap the cognitive benefits of physical activity.
Physical activity not only helps the hippocampus, but also the key brain center responsible for regulation of fear (your amygdala). Disorders of the amygdala coincide with increased feelings of distress and anxiety. In rodents, aerobic exercise buffers against this dysfunctional activation of the amygdala, according to recent studies. This suggests that simply being active helps to reduce the effect of stressors on mood.
Exercise also alters the way your brain produces and uses neurotransmitters. These plastic changes in functional brain areas influence the dopamine and serotonin pathways. As our brains produce more of these crucial chemicals, feelings of well-being and contentment increase. Your brain undergoes rapid, permanent change and your ability to cope with acute stressors increases.
Neurotransmitters affecting mood and nervous system health and causing increased feelings of stress and decreased emotional coping capabilities (glutamate and GABA) are elevated post-exercise. This suggests changes in connectivity across the brain itself i.e.plasticity.
You can benefit regardless of your - exercise preserves your brain health. Physical activity actually “de-ages” certain parts of older adults’ brains. (Older adults are placed at a significant risk for depression and cognitive decline.) Brains look “younger” in people who exercise. The part of your brain responsible for long term memory (the hippocampus) can even appear up to 65 years younger with daily exercise throughout life.
73- to 85-year-olds adults engaging in regular exercise had hippocampi appearing similar to young, healthy brains aged only 20 to 59, according to a study at UC Irvine’s Memory Institute for Neurological Disorders (UCI MIND). This effect on the hippocampus could reasonably be suggested to extend to the preservation of brain tissue controlling mood, as well. Further research is needed to validate the neurobiological changes across different areas of the brain, but this study is very promising. At the heart of it, this discovery lays a groundbreaking foundation: shaping an understanding of how you can reap the mood-enhancing, and memory-boosting benefits of exercise well into your later years.
A prescription for exercise may be on the horizon
Exercise offers multiple benefits to brain health that include improved mood and memory. The relationship is so strong that scientists are trying to understand how best to design a “prescription” for exercise that keeps individuals both physically and cognitively healthy.
There are multiple reasons to wanting to use exercise as an early treatment option instead of drugs:
Physicians are reluctant to prescribe psychoactive medications, especially to adolescents. This is problematic, as adolescents are at an extreme risk for major depressive disorder. Moderate daily exercise has been demonstrated to mitigate stress and low mood. It is worth considering as a viable “first line” of therapy.
Exercise has been proven to combat the negative effects of chronic pain on mood. It can even speed recovery of joint pain and inflammation. Inactivity can cause muscle weakness and atrophy. Regular light aerobic exercise such as walking, and cycling can improve outcomes for chronic pain sufferers. There is a clear correlation between chronic pain and depression. Chronic pain patients often report low mood that can be indicative of major depressive disorder. As sufferers continue to exercise, their mood will elevate, and in turn, their pain will decrease over time.
Moderate aerobic activity provides near-immediate effects on mood, whereas common antidepressants (such as SSRIs and SNRIs) take an average of six weeks.
The arguments for using exercise as an early intervention are strong.Trying to estimate and assign an optimal exercise program for an individual, gets a little more complex. There are no reliable, randomized controlled clinical trials comparing exercise programs and their relationship to mood. Preclinical human studies suggest moderate to intense bouts of aerobic activity can award substantial cognitive benefits. Establishing a benchmark amount is tricky. Exercising yourself to exhaustion only increases subjective feelings of pain and stress, and too little exercise will provide no benefit.
Consistency is also key. Missing a day or two of your exercise routine can leave you feeling a bit “off”. The exact length or intensity of your exercise routine is flexible, but a consistent and sustainable schedule is critical. This is where Injurymap can help you get, and stay on track.
You can benefit from consistent exercise, no matter your age or baseline activity level. Exercise is one of the few natural remedies providing huge payoff with minimal risk - validated by science.It can be a valuable addition to your life, if you want to feel happier, calmer and healthier. Our neurons, white matter, and critical brain areas are part of this wonderfully complex framework affected positively by exercise.
Exercise may not be a magical cure-all pill but evidence supports its introduction into a reliable therapy plan. The effects of physical exercise should be maximised with behavioral therapy and lifestyle changes. Exercise is not the only solution but a crucial part of it. Injurymaps gives you the tools to track your recovery and measure how different you feel after ramping up your routine.
Science provides us with important clues to living a healthier, happier life. One of the most interesting parts of neuroscience is that the answers are always scrutinized. Treatment, medicine and therapies are constantly being updated with the latest research. The impact of exercise on mental health is riveting, but the answers are still being discovered. Your supercomputer-like brain that is all neurons, chemicals and seahorses deserves the best treatment available. This includes exercise.
About the author
Blake Alec Miranda is a science writer based in California. He graduated from the University of California, Irvine with a degree in Cognitive Science, where he conducted research studying neurological diseases and child psychology. He spends his days coordinating clinical trials and writing about neuroscience.
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