# Exercise is critical to brain development > If there were a drug that could do for human health everything that exercise can, it would likely be the most valuable pharmaceutical ever developed. — Dr Mark Tarnopolsky Exercise is said to make you lose weight and to improve your heart health. In fact, it is still not clear whether exercise causes weight loss. What is clear, however, is that exercise makes you build muscle. But it does much more than that. Dr Daniel Wolpert argues that "we have a brain for one reason only: to produce adaptable and complex movements". The brain is a product of evolution which allowed us to perform complex tasks and thus to survive in hostile environments. Conversely, exercise, and movement in general, signals to our brain that something important is happening: are we hunting for food, or escaping from a predator? Indeed, exercise has been shown to increase brain-derived neurotrophic factor (BDNF) production: BDNF is a protein which promotes the function and growth and neurons, and protects them against cell death. What is more, exercise boosts motivation by increasing dopamine storage and promoting the creation of dopamine receptors in the reward centre (contra [[Addiction is caused by dopamine down-regulation]]). It elevates levels of norepinephrine and serotonin, hormones associated with alertness and energy for the former, and mood and emotional stability for the latter, and it decreases cortisol, the main hormone responsible for stress. As a result, people who exercise are less depressed, less anxious, less neurotic and more socially outgoing. --- ## 📚 References - [[@whativelearnedWhyExerciseUnderrated2016|WHY Exercise is so Underrated (Brain Power & Movement Link)]]