The Brain on Exercise: 

How Movement Transforms 

Mental Performance and Emotional Health

By Sigurd Stubsjoen and chatgpt

Introduction: A Revolution in Brain Science

For decades, exercise was primarily associated with physical fitness, weight loss, and cardiovascular health. But groundbreaking research, including the insights from Dr. John J. Ratey's book Spark: The Revolutionary New Science of Exercise and the Brain, has reshaped our understanding of how movement affects the mind. Exercise is not just about staying fit—it is a powerful tool for enhancing cognitive function, emotional resilience, and long-term brain health. From boosting neurotransmitters to promoting neurogenesis and reducing stress, movement is essential for a sharper, healthier brain.

1. Exercise and Neurotransmitters: The Brain’s Chemical Boost

Example from Spark: At Naperville Central High School, students who engaged in morning exercise programs dramatically outperformed their peers in standardized tests. Their results in math and science far exceeded the national average, illustrating how movement enhances learning and cognitive function.

The Science Behind It:

• Dopamine increases with exercise, enhancing motivation, focus, and reward-seeking behavior.
• Serotonin levels rise, improving mood and reducing anxiety.
• Norepinephrine boosts alertness and cognitive agility.

Real-World Application: Given these effects, exercise is now widely recommended as a treatment for ADHD, either as a natural supplement or an alternative to medication like Ritalin. Studies show that regular movement helps improve impulse control and attention span, making physical activity an essential tool for cognitive performance.

2. Neurogenesis and Brain Plasticity: The Role of BDNF

Example from Spark: Dr. Ratey highlights studies where aerobic exercise significantly increases levels of brain-derived neurotrophic factor (BDNF), a protein critical for memory and learning. In experiments with rats, those that exercised had double the BDNF levels of their sedentary counterparts.

The Science Behind It:

• BDNF functions as brain fertilizer, promoting the growth and survival of neurons.
• Exercise strengthens synaptic connections, improving information retention and recall.
• It stimulates neurogenesis, particularly in the hippocampus, slowing cognitive decline.

Real-World Application: Educational systems worldwide have begun integrating movement before learning sessions. Finland’s education model, which includes frequent breaks for physical activity, has demonstrated higher retention rates and improved academic performance. Similarly, elderly individuals who stay active experience less cognitive decline and lower risks of neurodegenerative diseases like Alzheimer’s.

3. Stress Reduction: How Exercise Regulates the HPA Axis

Example from Spark: Research reveals that individuals who engage in regular physical activity have lower cortisol responses to stress, making them more resilient in high-pressure situations.

The Science Behind It:

• The hypothalamic-pituitary-adrenal (HPA) axis regulates stress responses, and exercise helps balance its activity.
• Physical activity reduces excessive cortisol production, which can damage brain cells when chronically elevated.
• Movement stimulates the parasympathetic nervous system, promoting relaxation and recovery.

Real-World Application: Many high-stress professions, including emergency responders and surgeons, incorporate structured exercise into their routines. High-intensity interval training (HIIT) and yoga are particularly effective at mitigating stress-related symptoms, helping professionals maintain peak cognitive function under pressure.

4. Cognition and Learning: Exercise as a Brain Enhancer

Example from Spark: Students at Naperville who ran for 30 minutes before math and reading lessons consistently outperformed their non-exercising peers.

The Science Behind It:

• Exercise increases cerebral blood flow, delivering more oxygen and nutrients to the brain.
• The prefrontal cortex, responsible for decision-making and problem-solving, becomes more active.
• Memory consolidation is enhanced due to hippocampal stimulation.

Real-World Application: Corporate leaders and entrepreneurs have embraced this science. Many Silicon Valley executives engage in daily exercise to boost productivity and creativity, while companies like Google and Facebook provide on-site gyms to enhance employee cognitive performance.

5. Mental Health and Emotional Regulation: The Natural Antidepressant

Example from Spark: A Duke University study found that exercise is as effective as antidepressants for treating mild to moderate depression. Patients who followed a four-month exercise regimen experienced the same mood improvements as those on medication.

The Science Behind It:

• Serotonin production is increased, stabilizing mood and reducing anxiety.
• The endocannabinoid system, which regulates pleasure and relaxation, is activated.
• Beta-endorphins are released, producing the well-known “runner’s high.”

Real-World Application: In Scandinavian countries, exercise is prescribed as part of mental health treatment. Programs like Green Exercise (outdoor movement in nature) have shown significant reductions in symptoms of PTSD and anxiety.

6. Metabolic and Hormonal Effects: The Brain’s Energy Balance

Example from Spark: Studies indicate that exercise improves insulin sensitivity, lowering the risk of Type 2 diabetes—a condition strongly linked to cognitive decline.

The Science Behind It:

• Glucose metabolism is optimized, ensuring a steady energy supply to the brain.
• Insulin resistance, which contributes to neuronal damage, is reduced.
• Exercise balances estrogen and testosterone, both of which influence mood and cognition.

Real-World Application: Patients with prediabetes who adopt an active lifestyle significantly reduce their risk of developing Alzheimer’s disease. Since high blood sugar and insulin resistance accelerate neurodegeneration, exercise serves as a crucial preventive measure.

7. Aging and Brain Protection: Preventing Neurodegenerative Diseases

Example from Spark: Harvard research cited by Ratey shows that elderly adults who engage in regular aerobic exercise maintain larger hippocampal volumes, resulting in less shrinkage and memory loss.

The Science Behind It:

• Exercise reduces inflammation, a major factor in brain aging.
• It preserves telomere length, a key indicator of cellular longevity.
• Oxidative stress is mitigated, protecting neurons from damage.

Real-World Application: Japan’s daily movement culture contributes to some of the lowest dementia rates worldwide. In contrast, Western countries with more sedentary lifestyles show higher rates of neurodegenerative conditions, reinforcing the link between exercise and brain health.

Conclusion: Movement as Medicine

Dr. John J. Ratey’s Spark presents a compelling case: exercise is not optional—it is essential for brain function, emotional stability, and lifelong cognitive health. Whether you seek sharper focus, reduced stress, or long-term protection against cognitive decline, movement is a non-negotiable pillar of well-being. The evidence is clear: if you want a healthier brain, start moving today.