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Summary: Spark: The Revolutionary New Science of Exercise and the Brain by John Ratey

“Right now the front of your brain is firing signals about what you’re reading, and how much of it you soak up has a lot to do with whether there is a proper balance of neurochemicals and growth factors to bind neurons together. Exercise has a documented, dramatic effect on these essential ingredients.” – John Ratey MD

Exercise accelerates learning

When you exercise, your body naturally releases a protein called ‘brain-derived neurotrophic factor (BDNF)’ into the bloodstream and up to the brain. In the 1990s, scientists discovered BDNF rapidly accelerates brain cell growth and increases the ability to learn.

Book Summary: Spark - The Revolutionary New Science of Exercise and the Brain

“Researchers found that if they sprinkled BDNF onto neurons in a petri dish, the cells automatically sprouted new branches, producing the same structural growth required for learning—and causing me to think of BDNF as Miracle-Gro for the brain…BDNF gathers in reserve pools near the synapses and is unleashed when we get our blood pumping.” – John Ratey MD

“Exercise sparks the master molecule of the learning process” – John Ratey MD

Exercise enhances creativity

During exercise, the hippocampus brain region receives a large amount of BDNF growth factor. The hippocampus acts like a cartographer for the brain – linking new information to existing memories.

“A memory, scientists believe, is a collection of information fragments dispersed throughout the brain. The hippocampus serves as a way station, receiving the fragments from the cortex, and then bundling them together and sending them back up as a map of a unique new pattern of connections.” – John Ratey MD

Exercise sparks growth in the hippocampus, helping you create new connections between existing ideas and allowing you to come up with novel solutions to complex problems.

“If you have an important afternoon brainstorming session scheduled, going for a short, intense run during lunchtime is a smart idea.” – John Ratey MD

What’s the most ‘productive’ way to exercise?

Largest cognitive benefits in the least amount time, done sustainably


The most effective form of exercise for increasing mental performance is aerobic exercise (also known as cardio). Aerobic exercise includes any activity that pushes your heart and lungs for a sustained period. Examples include running, biking, and swimming. Although weight training is essential for physical health, it won’t provide the cognitive benefits aerobic exercise does.


Schedule your aerobic exercise before learning a difficult subject, tackling a complex project, or conducting a brainstorming.


Exercise for 20-30 minutes with at sustained heart rate of 60-70% of your maximum heart rate (max heart rate = 208 – (0.7)*current age). If you exceed 70% of your maximum heart rate, you’ll start burning reserve fuel (glycogen) and releasing large amounts of lactic acid, which breaks down muscle. The more time you spend above 70% of your maximum heart rate, the more recovery time you’ll need between exercises, and the less often you’ll reap the cognitive benefits of exercise. If you don’t have a heart rate monitor, don’t worry. Iowa State University kinesiologist Panteleimon Ekkekakis has found moving at a pace which feels “somewhat hard” is a good indication you are exercising near 70% of your maximum heart rate.

You experience the largest mental gains when you combine aerobic exercise with an activity that requires advanced motor skills:

“Choose a sport that simultaneously taxes the cardiovascular system and the brain—tennis is a good example—or do a ten-minute aerobic warm-up before something nonaerobic and skill-based, such as rock climbing or balance drills. While aerobic exercise elevates neurotransmitters, creates new blood vessels that pipe in growth factors, and spawns new cells, complex activities put all that material to use by strengthening and expanding networks. The more complex the movements, the more complex the synaptic connections.” – John Ratey MD

“In order for man to succeed in life, God provided him with two means, education and physical activity. Not separately, one for the soul and the other for the body, but for the two together. With these two means, man can attain perfection.” – Plato


Spark is a book that explores the powerful effects of physical exercise on the brain. The author, John Ratey, is a psychiatrist and a professor at Harvard Medical School who has been studying the link between exercise and mental health for decades. He presents compelling evidence from neuroscience, psychology, and medicine to show how exercise can improve learning, memory, mood, attention, creativity, and even prevent or treat various brain disorders.

The book is divided into ten chapters, each focusing on a different aspect of the brain-exercise connection. The first chapter introduces the concept of neuroplasticity, which is the ability of the brain to change and adapt in response to stimuli. Ratey explains how exercise stimulates the production of brain-derived neurotrophic factor (BDNF), a protein that acts like “Miracle-Gro for the brain”, enhancing its growth and repair. He also describes how exercise boosts other neurotransmitters, such as dopamine, serotonin, and norepinephrine, which are involved in motivation, reward, emotion, and stress regulation.

The following chapters explore how exercise can benefit various populations and situations, such as:

  • Students: Ratey cites several studies and examples that show how exercise can enhance academic performance, attention span, and cognitive skills in children and adolescents. He also discusses how exercise can help prevent or reduce the symptoms of attention deficit hyperactivity disorder (ADHD), dyslexia, and autism spectrum disorder (ASD).
  • Women: Ratey examines how exercise can help women cope with hormonal changes, such as premenstrual syndrome (PMS), pregnancy, menopause, and postpartum depression. He also addresses how exercise can protect women from developing Alzheimer’s disease, which affects women more than men.
  • Aging: Ratey explains how exercise can slow down the aging process of the brain and prevent or delay cognitive decline and dementia. He also shares how exercise can improve mood, social interaction, and quality of life in older adults.
  • Stress: Ratey describes how exercise can act as a natural antidepressant and anxiolytic, by reducing the levels of cortisol (the stress hormone) and increasing the levels of endorphins (the natural painkillers). He also suggests how exercise can help people cope with traumatic events, such as post-traumatic stress disorder (PTSD), abuse, or violence.
  • Anxiety: Ratey explores how exercise can reduce anxiety and panic attacks by regulating the activity of the amygdala (the fear center of the brain) and increasing the activity of the prefrontal cortex (the rational part of the brain). He also provides tips on how to use exercise as a tool for exposure therapy, which is a proven method for overcoming phobias and obsessive-compulsive disorder (OCD).
  • Depression: Ratey argues that exercise can be as effective as medication for treating mild to moderate depression, by increasing the levels of serotonin (the happiness chemical) and neurogenesis (the creation of new brain cells). He also discusses how exercise can help people with bipolar disorder, seasonal affective disorder (SAD), and suicidal thoughts.
  • Addiction: Ratey reveals how exercise can help people overcome addiction by rewiring the reward circuitry of the brain and reducing cravings and withdrawal symptoms. He also explains how exercise can help people with eating disorders, such as anorexia nervosa and bulimia nervosa.
  • Hormones: Ratey examines how exercise can balance the hormones that affect mood, appetite, metabolism, sexuality, and reproduction. He also covers how exercise can influence the levels of testosterone (the male hormone), estrogen (the female hormone), growth hormone (the youth hormone), and insulin (the sugar hormone).
  • Learning: Ratey demonstrates how exercise can boost learning and memory by increasing blood flow, oxygen, glucose, and nutrients to the brain. He also shows how exercise can enhance creativity and problem-solving skills by stimulating the growth of new connections between brain cells.
  • The Zone: Ratey describes how exercise can induce a state of flow or optimal experience, where people feel fully immersed, focused, and energized by what they are doing. He also explains how exercise can increase mindfulness and awareness of one’s body and surroundings.

The book concludes with a chapter on how to design an optimal exercise program for one’s brain health. Ratey recommends doing aerobic exercises that raise one’s heart rate to 65-75% of its maximum for at least 30 minutes three times a week. He also suggests adding some strength training, flexibility training, balance training, coordination training, and interval training to enhance one’s physical fitness and mental agility.

Here are the key takeaways from the book:

  • Exercise stimulates the growth of new brain cells: Ratey explains how regular physical activity promotes neurogenesis, the process of creating new neurons in the brain. This phenomenon can lead to improved cognitive function, particularly in areas such as memory and learning.
  • Exercise can reverse the effects of aging on the brain: The book highlights numerous studies showing that exercise can counteract age-related declines in brain function, such as reduced cognitive performance, reduced volume of gray matter, and impaired insular cortex function.
  • Exercise improves mental health: Ratey discusses the positive impact of exercise on mental health, including reducing symptoms of depression, anxiety, and ADHD. He also explores the link between exercise and increased levels of neurotransmitters such as dopamine and endorphins, which can contribute to improved mood and cognitive function.
  • Physical activity can enhance cognitive performance: The book delves into the science behind how exercise can improve cognitive function, including attention, concentration, and problem-solving abilities.
  • The brain and body are intricately connected: Ratey highlights the interconnectedness of the brain and body, demonstrating how physical activity can have a profound impact on overall health and well-being.
  • Exercise can help treat and prevent neurological disorders: The book discusses the potential of exercise to treat and prevent various neurological disorders, such as Parkinson’s disease, multiple sclerosis, and stroke.The timing and duration of exercise matter: Ratey emphasizes the importance of both the timing and duration of exercise when it comes to cognitive function, recommending that exercise should be incorporated into daily routines consistently and for at least 30 minutes per session.
  • Exercise can enhance creativity and productivity: The book explores the link between exercise and creativity, revealing how physical activity can boost cognitive flexibility, leading to improved problem-solving skills and innovation.
  • Exercise can improve sleep: Ratey discusses the sleep-exercise connection, explaining how physical activity can help regulate sleep patterns and improve overall sleep quality.
  • The book provides actionable tips for incorporating exercise into daily life: Ratey offers practical advice on how to incorporate exercise into daily routines, including setting realistic goals, finding activities that enjoy, and tracking progress.

Spark is a book that will inspire you to adopt a more active lifestyle and enjoy its benefits for your mind and body. It will provide you with scientific evidence and practical advice that can help you improve your brain functions and mental health. It will also challenge you to think differently and positively about how to overcome challenges and seize opportunities. Whether you are a student, a worker, a leader, or a learner, you will find something valuable and relevant in this book.

Overall, Spark: The Revolutionary New Science of Exercise and the Brain is an enlightening book that sheds light on the transformative effects of exercise on our mental well-being. It serves as a powerful reminder of the importance of physical activity in maintaining a healthy brain and offers a compelling argument for making exercise a priority in our lives.

In conclusion, “Spark: The Revolutionary New Science of Exercise and the Brain” is a thought-provoking and informative book that sheds light on the transformative power of exercise on our mental well-being. John Ratey successfully presents a compelling case for incorporating physical activity into our daily lives, illustrating how exercise can improve our cognitive abilities, emotional resilience, and overall brain health. Whether you are a fitness enthusiast or someone looking to enhance their mental performance, this book offers valuable insights and practical advice that can benefit readers of all backgrounds.

Here are some additional thoughts on the book:

  • I appreciate that Ratey provides a clear and concise explanation of the brain-body connection. This makes it easy to understand the concept and start applying it in your own life.
  • I also appreciate that Ratey provides a variety of practical tips for getting started with an exercise program. This gives you a lot of options to choose from and helps you to find the approach that works best for you.
  • I think the book is most helpful for people who are already working on improving their brain function. It can help you to stay motivated and focused on your goals by providing you with a framework for tracking your progress and celebrating your successes.

If you are interested in learning more about the benefits of exercise for the brain, I highly recommend reading Spark.

Alex Lim is a certified book reviewer and editor with over 10 years of experience in the publishing industry. He has reviewed hundreds of books for reputable magazines and websites, such as The New York Times, The Guardian, and Goodreads. Alex has a master’s degree in comparative literature from Harvard University and a PhD in literary criticism from Oxford University. He is also the author of several acclaimed books on literary theory and analysis, such as The Art of Reading and How to Write a Book Review. Alex lives in London, England with his wife and two children. You can contact him at [email protected] or follow him on Website | Twitter | Facebook

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