I was shocked to learn that my brain has not stopped growing…
For decades I, along with researchers, believed that as we age individual neurons in our brain started dying off, that the loss was permanent and that the brain couldn’t make new nerve cells to replace the dead ones. We seniors seemed doomed to an eventual life of confused doddering, senility or, at the very least, forgetting the grandchildren’s names.
Recently, researchers announced that they had succeeded in stimulating the human brain into growing new brain cells by putting subjects on a three month aerobic workout regimen. Other experts have discovered that vigorous and complex exercises can stimulate older brain cells to form dense, interconnected webs that make the brain run faster and more efficiently. So it seems that we can not only build capacity in some parts of the brain but also improve the overall operation.
In his book “Spark: The Revolutionary New Science of Exercise and the Brain,” John J. Ratey, MD, clinical associate professor of psychiatry at Harvard Medical School, explained the basic science in layman’s terms. Every time a muscle contracts and releases it sends out chemicals, including a protein called IGF-1 that travels through the bloodstream and into the brain. There it stimulates the production of several chemicals, including one called brain- derived neurotrophic factor, or BDNF, that fuels almost all of the activities that lead to higher thought. Ratey calls it, “miracle grow for the brain.”
Until recently it was thought that, although people maintain relatively constant levels of BDNF through adult years, individual neurons gradually die off. The accepted conclusion was that no new nerve cells were manufactured to replace the old; lost and gone forever. A recent study, published in the proceedings of the National Academy of Sciences, reaches a different conclusion. After the three month aerobic workout regime, all the participants showed new neuron growth. The supposition was that it was BDNF at work, transforming stem cells into full-grown functional neurons.
Further observation showed that that new neurons created appeared in only one part of the brain, the area that controls learning and memory, the hippocampus. That region helps the brain match names to faces- one of the first skills to suffer as we age. The area has also proven to be especially responsive to BDNF’s effects, apparently restoring it to a healthier, more youthful state. “It’s not just a matter of slowing down the aging process,” says Arthur Kramer, a psychologist at the University of Illinois. “It’s a matter of reversing it.”
Although it is thought that new neurons can’t grow throughout the rest of the brain, there are other proven secondary benefits to the brain and neurological system from a good exercise session. Exercise increases blood volume and new capillaries which, in turn, lessens inflammation in the brain and the occurrence of mini-strokes says neuroscientist Kristine Yaffe. John Ratey also notes that levels of neurotransmitters like dopamine, serotonin and norepinephrine are elevated after a workout. “So having a workout will help with focus, calming down, impulsivity- its like taking a little bit of Prozac and a little bit of Ritalin.”
UCLA neuroscientist Fernando Gomez-Pinilla points out that humans have evolved to thrive on physical activity. Without regular exercise, “our brains aren’t doing what they are supposed to do.” Some early research suggests that people who exercise frequently tend to develop Alzheimer’s less often and, if so, later in life. Other research shows that one of Alzheimer’s first targets is the hippocampus, the main beneficiary of vigorous exercise and the resultant BDNF.
The best news of all is that age is not a factor in this equation. As long as we continue to exercise, we reap the benefits of more and better operating brain cells. The mind-body connection is a fascinating subject. Its never too late to learn that lesson.