This video will examine the impact that exercise has on the brain. When we think about the benefits of exercise, attention is usually focused on the heart, lungs and muscles. However, as it turns out, the brain is very active during a single bout of exercise. This includes both enhanced neuroelectrical activity, as well as increased brain blood flow. While much still needs to be learned regarding the impact of exercise on the brain, I will discuss what we know in four major areas of brain research. The implications for these adaptations are great, as it can help maintain or improve cognitive function, reduce age-related dementia, including Alzheimer's Disease, treat symptoms of Parkinson's Disease, lessen the severity of depression and anxiety, and reduce the negative effects of chronic stress. When discussing the major factors contributing to and maintaining a healthy brain, the primary components are regular exercise, a healthy diet, mental stimulation, stress management, sleep quality and an active social life. Exercise has the potential to influence all of these factors. Various regions in the brain are activated during excercise. This includes the prefrontal and motor cortex, hypothalamus, hippocampus, and frontal lobe. Shown here is the neural electrical activity in the human brain during mild exercise and at rest. The areas in blue indicate minimal brain activity, while the other colors indicate various degrees of neural activity. Clearly, exercise stimulates activity in multiple regions of the brain. Further, during exercise, blood flow to the brain can increase by as much as 20%. As vascular degeneration in the brain is a common cause for dementia and eventual Alzheimer's disease, the ability to maintain brain blood flow is of critical importance. As such, exercise has been shown to play a key role in cognitive function and the reduction of dementia. Dementia is defined as the loss of mental function in two or more areas such as language, visual and spatial abilities, memory, thinking and reasoning, or judgement. Alzheimer's disease is the most common cause of dementia. It is a degenerative diseases that attacks the brain gradually over time. According to the Center for Disease Control, Alzheimer disease ranks as the sixth leading cause of death. The major non-modifiable risk factors for Alzheimer's disease include advancing age, family history, and gender. Among the modifiable risk factors, please notice that regular exercise not only lowers the risk factor for Alzheimer's disease, but as we have discussed for other diseases, it lowers the risk of many other of the modifiable risk factors such as hypertension, high cholesterol, obesity, and diabetes. Here are the results of one of the many studies demonstrating that regular exercise can reduce the risk of dementia as well as delay the onset of Alzheimer's disease. While not fully understood, the potential mechanisms, whereby exercise can exert this protective effect in the brain, are shown here. First, as all ready mentioned, exercise can reduce several of the other modifiable risk factors. Second, as will be discussed at the end of this video, exercise can reduce the negative effects of chronic stress on the brain. Finally, exercise can help maintain brain blood flow and increase glucagon-like peptide one. Both of which, can reduce the accumulation of beta amyloid plaques synonymous with Alzheimer's disease. Now, let's look at a different brain disorder. Parkinson's disease is a neurodegenerative brain disorder that progresses slowly in most patients. Basically, the brain slowly stops producing the neurotransmitter, dopamine. As a result, a person has less ability to regulate their muscle movements and body coordination. Symptoms include slowness of movement, involuntary shaking or tremors at rest, and stiffness of the arms, legs, or trunk. Difficulty with balance and frequency of falls is also associated with Parkinson's disease. The mechanisms whereby exercise reduces the symptoms of Parkinson's disease have not been clearly elucidated. However, its effectiveness in treating the symptoms of Parkinson's disease continues to mount. Evidence is accumulating that exercise may strengthen and improve motor circuitry through mechanisms that include increased synaptic strength resulting from raised dopamine neural transmissions. Exercise also leads to increased expression of neurotropic factors, increased brain blood flow and increased neurogenesis, the formation of new brain neurons. Next, examine how exercise can help alleviate the symptoms associated with depression. Worldwide, 350 million people suffer from depression. Common symptoms include a depressed mood, and feelings of sadness, fatigue, sleep disruption, changes in appetite and body weight, reduced interest in life events, hopelessness, and suicide. Major risk factors include female gender, physical inactivity, family history, stress social isolation and a chronic health condition. Research continues to surface demonstrating the anti-depressant effects of exercise. I will show you just a few of the many studies. First, an inverse relationship exist between the amount of exercise performed and the incidents of clinical depression. Thus, the greater involvement in regular excercise, the less is the risk for clinical depression. In the studies shown here, just two aerobic exercise sessions per week, of 20 to 30 minutes, were sufficient to dramatically reduce depression and tension scores in both men and women after the 12 week intervention. When examining over 150 adults with mild or moderate depression, a four month period of supervised intervention consisting of either treatment with an antidepressant drug or 45 minutes of aerobic exercise or a combination of both, improvements were seen in over 50% of the patients. However, the following six months, subjects were welcomed to voluntarily continue their treatment on their own. Notice that at the 10 month time point, over 85% of the patients in the exercise-only group remained depression free after 6 months on their own. In addition to the biochemical changes in the brain, a feeling of empowerment and self confidence were suggested as reasons for this anti-depressive effect of exercise. Finally, as discussed in a previous video, I want to remind you of the stress reducing effects of regular exercise. Physical activity can significantly lower negative effects that chronic stress can have on the body thereby imparting some degree of stress resistance. Shown here are some of the more serious side effects from chronic stress and the counter benefits associated with exercise. In summary, regular exercise is excellent medicine for the prevention and treatment of many brain disorders including dementia and Alzheimer's disease, Parkinson's disease, depression, and chronic stress. This concludes my course on the science of exercise. I hope you have enjoyed taking it as much as I have enjoyed teaching it. You may also enjoy the assessments that I have provided for the course, which include discussion prompts, end of module quizzes, application assignments, and a final project. Thanks for watching, now get out there and spread the word about the many benefits of exercise.
