Physical exercise: why aerobic exercise enhances neurogenesis and neuroplasticity
As little as three hours a week of brisk walking has been shown to halt, and even reverse, the brain atrophy (shrinkage) that starts in a person’s forties, especially in the regions responsible for memory and higher cognition. Exercise increases the brain’s volume of gray matter (actual neurons) and white matter (connections between neurons).
Through increased blood flow to the brain, physical exercise triggers biochemical changes that spur neuroplasticity – the production of new connections between neurons and even of neurons themselves. Brain exercise then protects these fledgling neurons by bathing them in a nerve growth factor and forming functional connections with neighboring neurons. Dr. Gage’s work of the Salk Institute for Biological Studies, have shown that exercise helps generate new brain cells, even in the aging brain.
Studying this topic, Dr. Smeyne of the Saint Jude Children’s Research Hospital in Memphis, found that results could be seen in two months in Parkinson patients. Parkinson patients demonstrate a progressive loss of dopamine neurons in the substantia nigra pars. After two months of exercise, the patients had more brain cells. Higher levels of exercise were shown to be significantly more beneficial than lower amounts, although any exercise was better than none. Smeyne also found that starting an exercise program early in life was an effective way to lower the risk of developing Parkinson’s disease later in life.
Numerous animal studies have shown that physical exercise has a multitude of effects on the brain beyond neurogenesis, including increases in various neurotransmitters and nerve growth factor levels, and angiogenesis (the formation of new blood vessels).
In 2003, Dr. Colcombe and Kramer, analyzed the results of 18 scientific studies published between 2000 and 2001. The results of this meta-analysis clearly showed that physical fitness training increases cognitive performance in healthy adults between the ages of 55 and 80.
Another meta-analysis published in 2004 by Dr. Heyn and colleagues shows similar beneficial effects of fitness training for people over 65 years old who had cognitive impairment or dementia.
What type of exercises is needed?
According to Dr. Art Kramer, aerobic exercise, at least thirty to sixty minutes per day, three days a week, has been shown to have a positive impact on brain functions. Importantly, the exercise does not have to be strenuous, walking have been shown to have positive effects too.
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This new online resource is based on the content from the book The SharpBrains Guide to Brain Fitness (May 2009, $19.95), by Alvaro Fernandez and Dr. Elkhonon Goldberg.
