THE ARTICLE
Regular exercise can potentially help improve a host of conditions from depression to memory to Dementia. And even for those without any particular brain conditions, exercise is a natural painkiller and mood elevator.
Almost a decade ago, a team from Duke University published research showing that aerobic exercise causes significant improvements in higher mental processes such as planning, organisation, and juggling multiple tasks. "What we found so fascinating was that exercise had its beneficial effect in specific areas of cognitive function that are rooted in the frontal and pre-frontal regions of the brain," said James Blumenthal, Duke psychologist and study principal investigator. Interestingly, certain other brain functions such as attention, concentration, and psychomotor skills, did not seem to be affected. The researchers believe the beneficial effects of aerobic exercise may be due to the improved flow of oxygen-rich blood to certain brain regions. Christin Anderson, MS, wellness and fitness coordinator of the University of San Francisco, says, "When you exercises, you can think more clearly, perform better, and your morale is better. This is pure science -- stimulate your nervous system and you will function at a higher level."
In addition to sharpening mental functioning, many people who exercise regularly note that they get a certain “high” from exercising. This euphoric feeling is attributed to endorphins, which are chemicals stimulated by the pituitary gland during exercise. Endorphins block the transmission of pain impulses in the brain, minimising discomfort and often resulting in euphoria. Interestingly, endorphins attach to the same neuron receptors as morphine and heroin, making them a powerful and somewhat addictive drug. However, exercise itself doesn’t seem to be highly addictive for most people. Perhaps this is due to the 30-minute delay in the release of endorphins from exercise, or to the somewhat complicated task of scheduling and maintaining an exercise program over time.
Another brain chemical stimulated by exercise is called brain-derived neurotrophic factor (BDNF). BDNF is a protein produced in the hippocampus, and has antidepressant-like properties. BDNF is found in lower levels in people with depression. Carl W. Cotman, PhD, and his colleagues at the University of California Irvine (UCI) have measured BDNF in the brains of rats in various age groups. "We found that the induction of BDNF in each age group rose significantly after one week of exercise," says Cotman. Interestingly, they also found that the older rats performed better in tasks related to depression. This result could mean that physical activity has a protective effect against depression, particularly in the elderly. "This is an exciting result," says Cotman. "Translated into human terms, it means that individuals who are appropriately physically active may be able to protect themselves from depression -- or be less depressed or relieved from depression -- if they are physically active." Further research will be needed to confirm this hypothesis in humans.
On a related note, one of the most exciting effects of exercise on the brain is the stimulation of neurogenesis. In the last decade researchers have discovered that the brain can produce new brain cells, something once thought to be impossible and a main reason for mental decline. To create these new brain cells, the brain needs a challenging environment, including mental and physical stimulation. Rats with exercise wheels showed significant increases in their number of brain cells as compared to rats without exercise wheels. Interestingly, researchers believe this growth is related to the activity being voluntary: rats forced to exercise in a swimming pool did not show an increase in the number of brain cells, and rats with exercise wheels voluntarily logged some four to six miles a day on their wheels.
The research on exercise and neurogenesis has led these scientists to speculate that exercise could have beneficial effects on the prevention of Alzheimer’s Disease and Dementia. New animal research by Cotman and his colleague, Paul Adlard, demonstrates that long-term physical activity enhanced the learning ability of mice and decreased the level of plaque-forming beta-amyloid protein fragments in their brains — a hallmark characteristic of Alzheimer's disease (AD). Compared to sedentary animals, mice that had exercised for 5 months on the running wheels had significantly fewer plaques and fewer beta-amyloid fragments (peptides) in the cerebral cortex and hippocampus, approximately by 50 percent. Additional studies, of exercised animals at 10 weeks old, showed that the mechanism underlying this difference began within the first month of exercise. These results concur with other studies published that indicate that beta-amyloid levels decreased in the brains of mice when they lived in an “enriched” environment with exercise wheels, colored tunnels and toys.
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