Exercise and the brain


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Exercise and the brain

  1. 1. Notes from the book Spark By John J. Ratey, MD
  2. 2. Why do we feel good when we exercise? Your ideas? It makes our brain function at its best. This is the most important benefit of exercise, the benefit to muscles, heart, and lungs are just healthy side-effects of exercise. Why is exercise so good for the brain?
  3. 3. In a Duke University study it was shown thatexercise was better than Zoloft (sertraline) attreating depression and other subsequentstudies have shown that exercise may be one ofthe best treatments for most psychiatricproblems. WHY?
  4. 4. Only mobile creatures need a brain. Sea Squirt Larva have brain, it is consumed once it becomes sessile.
  5. 5. “That which we call thinking is the evolutionaryinternalization of movement.” Neurophysiologist Rodolfo Llinas As we evolved, our physical skills developed into abstract abilities to predict, sequence, estimate, plan, rehearse, observe, judge, correct mistakes, shift tactics, and remember everything we did in order to survive.
  6. 6. Evolution of brain and body together over millions of years. The relationship between the ability to obtain food, shelter, comfort, and the physical ability to obtain them through learning that has been hardwired into the brain’s circuitry. In order to survive we had to use our brains to find and store food. We needed fuel to learn and learning to find a source of fuel. We needed to move! On average 11 km per day! Today, not so much 
  7. 7. Modern people don’t move as much creating a problem for us as individuals and a society.  65% adults in our nation are overweight.  10% have type 2 diabetes. 1/3 of the U.S. population by 2050.  Preventable health issues due to lack of exercise are becoming increasing more frequent in children.
  8. 8. Our lack of movement is reflected in what we value in education. Nationally we are cutting back on P.E. Illinois only state requiring P.E. on a daily basis. In school 5.5 hours of screen time per day per student. No or reduced recess for elementary education.
  9. 9. Naperville School District Case Study: School district one of the fittest in the nation. 3% overweight vs. 30% (national average) TIMSS (trends in Math and Science Study) tested out 6th in Math and 1st in Science. Why?
  10. 10. P.E. Revolution Fitness vs. Sports P. E. Only 3% of students go on to be active in sports after high school. Jr. High Teacher Phil Larson revolutionizes P.E. with fitness vs. Sports Program. Emphasizes personal best and assesses effort. Small scale sports ex. 3 on 3 basket ball, 4 on 4 soccer with the goal of movement. Graded on how much time student spent in target heart rate zone.
  11. 11. Heart rate monitors in class.
  12. 12. Zero hour P.E. at Naperville Central High School Like early bird P.E. (called learning readiness P.E.) incoming freshman assigned to reading comprehension literacy class. 17% improvement in reading comprehension vs. 10.7%
  13. 13. Other data: California Dept. of Ed. Students with the highest fitness scores had the highest test scores 2001 study fit kids scored 2x’s as well on academic tests as their unfit peers. Titusville, Pennsylvania, since adopting fitness P.E. the students improve at 17% higher in reading and 18% higher in math than state average. (Low median income) No fist fights in 550 jr. high kids since 2000. Kansas City Mo. P.E. went from once a week to once a day and violent incidences went from 228 in one year to 95. in another inner city school discipline problems dropped 67%
  14. 14. In order to learn the brain mustchange. Plasticity: The brain is designed so that it can change! The environment creates the impetus for change. What is your environment? What are your experiences When we learn we change our brains. The neuron allows us to do this.
  15. 15. Review of neuron function: Neurons by themselves are not very powerful. Neural networks- many neurons create communication lines between them in order to create perceptions and learn new things as we “experience” life Communication between neurons requires the molecules that move between them, what are they? Neurotransmitters.
  16. 16. The Neuron:
  17. 17. Neural Networks:
  18. 18. Neurotransmitter Cascade 80% of the signals in the brain rely on two main neurotransmitters: Glutamate, which stirs up the activity and begins the cascade GABA, which locks the brain activity down. These two neurotransmitters begin the chemical sequence of brain activity that regulates all of our behavior. In many cases they stimulate the release of many other neurotransmitters.
  19. 19. The other neurotransmitters: Regulatory neurotransmitters such as serotonin, norepinephrine, and dopamine. Only 1% of the neurons produce these n.t. They instruct other neurons to make more glutamate, alter the sensitivity of neuron dendrites, and signal other neurons to fire. fine tune the balance of the brain’s chemicals.
  20. 20. Serotonin: Considered the policeman of the brain It influences mood, impulsivity, anger, and aggression. Many drugs used for anxiety and depression stimulate the levels of serotonin in the brain.
  21. 21. Norepinephrine: Amplifies attention and perception as well as motivation. This is one of the hormones in adrenaline that is released during the fast part of the stress response. (fight/flight)
  22. 22. Dopamine: The key neurotransmitter involved in reward (satisfaction) attention and movement.
  23. 23. But raising or lowering their levels doesn’t elicita one to one result as the system is so complex.Consider the side effects of many of theneurotransmitter influencing drugs such asselective serotonin reuptake inhibitors (ssri)
  24. 24. Other Brain Chemicals: These are called “Factors” Most commonly called brain derived neurotrophic factors (BDNF.) They are a class of proteins. Build and maintain cell circuitry infrastructure. The best way to think of them is as fertilizer for the brain.
  25. 25. Brain Derived neurotrophicfactors (BDNF) In the 1990’s ~ one dozen or so scientific studies done on them. Explosion of neuroscience research after 2000. 5400 papers/studies done as of 2007. Why? Turns out there pretty darn important to the brain, its overall health and learning.
  26. 26. Learning requires strengthening therelationship (affinity) between neuronsthrough a dynamic mechanism called longterm potentiation. (building strong synapsesbetween the neurons makes it easier forsignaling/firing between them.)
  27. 27. Learning pathway explained Glutamate (a neurotransmitter) is sent from one neuron across the synapse to the dendrites of another. If there are repeated firings, the genes inside the receiving neuron are turned on to produce building materials for the synapse to allow it to become permanently more receptive. The memory sticks!
  28. 28. Learning and forgetting If you learn a new word each day and never practice it the attraction between synapses diminishes and you forget it. Repeated activation/stimulation comes with practice. This causes the synapse to swell actually growing more brain. So where does exercise come in?
  29. 29. Because so many parts of the brainare involved in movement, all of the brain is benefitted by movement.
  30. 30. Movement and exercise is where BDNF comes in to play. If you sprinkle BDNF on neurons in a petri-dish, the cells automatically sprouted new branches (synapses.) Like Miracle-Grow for the brain . Here’s how: 1) BDNF binds receptors at the synapse 2) activates genes that call for more BDNF, serotonin, and proteins that build synapse 3) BDNF builds & strengthens the neuron protecting against cell death
  31. 31. Exercise and Rats U of Cal Irvine: Carl Cotman director for brain aging used rats on a running wheel. (They were not forced to participate!)control vs. 2, 4, and 7 nights of running a week. Their BDNF went up relative to the amt. exercised. Their hippocampus lit up w/BDNF.
  32. 32. Exercises effect on the brain is immediate. 2007 German researchers found humans learned 20% faster following exercise Slowly psychiatry grudgingly accepts the idea that exercise can improve state of mind in all areas of treatment.
  33. 33. Understanding the context of Brain Derived Neurotrophic Factors BDNF are great but not just by themselves Need something to respond to. Challenge yourself and learn something after exercise. Environmental enrichment study on rats, by Dr. William Greenough from U. of I. (video)
  34. 34. The birth of new neurons throughout our life is a relatively new idea in neuroscience.
  35. 35. Exercise stimulates neurogenesis Pharmaceutical companies dream of finding the chemical pathway to induce neurogenesis. They want to put exercise into a bottle. Consider the implications? Not just BDNF but a host of other hormones and chemicals that stimulate both neuron growth and development but also glial cell growth.
  36. 36. So what’s the best exercise You can’t actually learn very well while exercising at a high intensity. (blood is move away from the prefrontal cortex.) But blood flow returns immediately after exercise. Find exercise that you like to do where heart rate is increased significantly. (30+minutes.) Running, swimming, biking. Mix in exercise that involves coordination: tennis, racquetball, balance drills, yoga, dance, skating, karate.
  37. 37. Summary of Exercise Benefits to the Brain: Increases alertness, attention, and motivation Prepares and encourages nerve cells to bind to one another-allowing logging of new information. Spawns the development of new nerve cells form stem cells in the hippocampus. Protects the cells from aging prematurely and death.
  38. 38. Other Brain Benefits from Exercise: Reduction of the effects of stress and anxiety Relief from depression. Improved concentration and performance from people diagnosed with ADHD. Addiction Hormonal changes Aging