The Interplay of Body, Brain, and Mind

Learn the importance of working on your body first to effect change in your brain and mind.

Composite image of a woman running at sunset through a silhouette of her sitting

Based on Dr. Jason Karp’s TED talk and adapted from the book, Work Out: The Revolutionary Method of Creating a Sound Body to Create a Sound Mind.

Somewhere between chasing other animals for food and clicking a mouse to purchase a toaster oven on Amazon, we stopped living a physical life. Instead, we are encouraged to work on our inner selves, to practice mindfulness and meditate. Social media gives us “Monday Motivation” and shouts daily positivity. Law of attraction followers say that our thoughts directly change our lives, that we can manifest what we want from the universe. Parents, teachers, Olympic athletes, and practically everyone else tell us that we can achieve anything we set our minds to. Prominent people tell us to start from our why and look inward to live our best life.

But that’s all wrong. Or, at least, incomplete.

We are physical animals, first. You think a lion asks himself, “What’s my why?” No! The lion is the king of the jungle. He acts like the king because he knows no other way. He uses his body every day to intimidate other animals, chase them for lunch, protect his family, and rule over his kingdom.

If we focus on the outside—making our physical bodies strong, resilient, enduring—that changes us on the inside. It strengthens our belief in ourselves and what we can do. It fills the hole created by insecurity.

This transformation isn’t some pseudo-holistic platitude, with false promises that making bigger biceps makes you confident and successful. It’s science. By working on the outside, you can actually alter your physiology, change your brain chemistry, and change your outlook on life … and on yourself.

Exercise is good for your brain

Many scientific studies have shown that exercise causes profound changes on the inside that positively affect your creativity, cognition, and confidence. In part, this happens because of the opioids and cannabinoids released in the brain that cause a perceived euphoria—the “runner’s high.” Then there’s the increase in serotonin that makes exercise even more effective than prescription drugs for ameliorating depression.

And then there’s neurogenesis—the formation of new neurons in the brain—that improves the way we think, including our problem solving, creativity, memory, and learning. Research has shown that people perform better on tests of creative thinking after exercise compared to when the tests are taken without exercising first.

Neurogenesis even occurs across different species: Research has shown that mice given access to a running wheel for a few months have more than twice the number of new cells formed in their brains compared to mice with no access to a running wheel. Whether you are a mouse or a human, a sound body creates a sound mind.

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The changes caused by exercise take place even at the cellular level, where the business of life occurs, and in the nucleic acids and bases that create the helical strands of your DNA. These changes all start by working out.

When you work out, you create a sound external, which creates a sound internal. You create a sound body, which creates a sound mind. When you create a sound body and mind, you are enabled and empowered to live the life you want, the life you care about, the life you desire. Your life doesn’t start from the inside. It starts from the outside. Because you are an animal.

Body, Brain, and Mind

Every human has three parts: Body, Brain, and Mind. When they work together and are equally balanced, life is great and hums along the way it’s supposed to. The Body would be strong, resilient, and enduring, the Brain would be buzzing with electrical activity, and the Mind would be analytical, confident, and emotionally intelligent—navigating challenges and figuring out solutions to problems.

Unfortunately, few people are blessed with such a balance. Body, Brain, and Mind often work in conflict with one another. They all want to be the boss. But there can be only one boss: the Body.

People tend to think that the Brain sits atop the pyramid, controlling the Body, but it’s actually the other way around. The Body is the Chief Executive Officer, and the Brain is the Chief Operating Officer.

While the Brain oversees your Body’s entire operation, it works in service to your Body. That’s what it evolved to do. Your Brain evolved from your Body’s movements to regulate your Body and manage its physiology so that it can efficiently move and interact with the world around you. Walking and running on two legs, which evolved from the anatomical change in the pelvis and is among the most complex and sophisticated of all physical movements, was the basis for the evolution of your Brain. Physical activity is so essential to your Brain that it is imperative for it to function properly.

But our lives have become unbalanced. Our Bodies were never meant to stop running and sit at our desks all day. Because the Body is the boss.

When we lose the ability to move the Body, we lose our Chief Executive Officer, and mental health—the functioning of the Brain and the Mind—rapidly declines. To live life fully, you need to see the Body and the Brain being interconnected parts of the same entity, of the same human experience.

Part of the process

The Body and the Brain are two parts of the same physical living being. Just because there is something unique about human cognition doesn’t mean that the Brain is independent from the Body. Our efforts to understand the nature of the human Brain should, therefore, be commensurate with our efforts to understand the nature of the Body and, ultimately, the nature of life.

Your heart, your muscles, your Brain, and all your other organs are parts. They mean little by themselves. You can’t understand the value of life’s process by separating the parts from the process, or the process from the parts. Parts without a process are the antithesis of life, devoid of motion and purpose.

To fully understand the role each part plays in your life, in the way you see and interact with the world, you have to see the Brain as part of your whole physical existence. Not separate from the whole, working at your desk by itself.

While the cells in your other organs, like your heart and kidneys, perform their assigned functions and don’t represent any other cells or functions, the cells of your Brain represent and even control functions occurring elsewhere in your Body. The Brain works with your heart, kidneys, muscles, lungs, blood vessels, the sensory neurons on your fingertips, and every other part of your Body to create your physical existence that enables the whole process to work. And it works the process by converting inputs from all its neurons, synapses, and neurotransmitters to outputs to create the thoughts, ideas, and perceptions that make up your Mind.

Training the Body changes the Brain, which affects the Mind. Training the Body eliminates the conflict between Body, Brain, and Mind, making all three parts work in harmony.

There are times in your life that will test you, that will throw you on your back. But if you remember where you came from, if you remember that you are indeed an animal with biology similar to that of many other animals, then you remember that to live life fully, you must live physically. And then you can train your Body to change your Brain to affect your Mind, connecting the three parts of yourself that create your earthly existence.

Practical tips to balance your Body, Brain, and Mind

  • See yourself as an animal. If you remember that you are an animal with biology similar to that of many other animals, then you remember that to live life fully, you must fully live physically.
  • Push your Body. Hard physical exercise can test and reveal resolve, courage, and endurance. Seek it out. You have the choice to learn just how far you can be pushed and how much you can endure. You can conquer the cowardice in yourself.
  • Do different types of workouts to challenge your Body in different ways. Look for endurance, strength, power, and cognitive flexibility workouts that include multiple movements and a high degree of skill, like circuit training, racquetball, or soccer.
  • Learn by doing. Instead of sitting at a desk or laying on your couch to read, learn by moving your body. Try reading while you walk on a treadmill or practicing a new physical skill.


  1. Boecker, H., Sprenger, T., Spilker, M.E., Henriksen, G., Koppenhoefer, M., Wagner, K.J., Valet, M., Berthele, A., and Tolle, T.R. The runner’s high: Opioidergic mechanisms in the human brain. Cerebral Cortex, 18(11):2523-2531, 2008.
  2. Saanijoki, T., Tuominen, L., Tuulari, J.J., Nummenmaa, L., Arponen, E., Kalliokoski, K., Hirvonen, J. Opioid release after high-intensity interval training in healthy human subjects. Neuropsychopharmacology, 43(2):246-254, 2018.
  3. Carek, P.J., Laibstain, S.E., and Carek, S.M. Exercise for the treatment of depression and anxiety. International Journal of Psychiatry in Medicine, 41(1):15-28, 2011.
  4. Bramble, D.M. and Lieberman, D.E. Endurance running and the evolution of Homo. Nature, 432(7015):345-352, 2004.

About the Author

Jason Karp, PhD, MBA, is a coach, exercise physiologist, writer, and TEDx speaker. He is the 2011 IDEA Personal Trainer of the Year and two-time recipient of the President’s Council on Sports, Fitness & Nutrition Community Leadership Award. His REVO₂LUTION RUNNING coaching certification, which has been obtained by coaches and fitness professionals in 26 countries, was acquired by International Sports Sciences Association in 2022. In 2021, Jason became the first American distance running coach to live and coach in Kenya. Work Out and his other books are available on Amazon and at