re MODEL your Brain!

All those early wake-up calls to make those before dawn exercise classes were doing more for me than I thought- according to researchers at Princeton University who were following a comprehensive experiment with running rats… They discovered that the neurons of the  brains of rats who exercise  respond remarkably different to – dare I say it- the couch potato rats… They concluded that the young  “cells born from running,” appeared to have been “specifically buffered from exposure to a stressful experience.”  Amazingly, the rats had created, through running, a brain that seemed biochemically, molecularly, calm.

We always intuited that  exercise enhanced our psychological states, but now  scientists are learning how exercise, a physiological activity,  directly affects mood and anxiety- that  exercise remodels the brain, making it more resistant to stress.

Exercise alters the activity of dopamine, a neurotransmitter in the brain, and appears to dampen the effects of oxidative stress. In an experiment led by researchers at the University of Houston and reported at the Society for Neuroscience meeting,” rats whose oxidative-stress levels had been artificially increased with injections of certain chemicals were extremely anxious when faced with unfamiliar terrain during laboratory testing. But rats that had exercised, even if they had received the oxidizing chemical, were relatively nonchalant under stress. When placed in the unfamiliar space, they didn’t run for dark corners and hide, like the unexercised rats. They insouciantly explored.”

“It looks more and more like the positive stress of exercise prepares cells and structures and pathways within the brain so that they’re more equipped to handle stress in other forms,” says Michael Hopkins, a graduate student affiliated with the Neurobiology of Learning and Memory Laboratory at Dartmouth. “It’s pretty amazing, really, that you can get this translation from the realm of purely physical stresses to the realm of psychological stressors.”

Alas, these stress-reducing changes on the brain  influenced  by exercise  don’t happen overnight.  In the University of Colorado experiments, for instance, rats that ran for only three weeks did not show much reduction in stress-induced anxiety, but those that ran for at least six weeks did. “Something happened between three and six weeks,” says Benjamin Greenwood, a research associate in the Department of Integrative Physiology at the University of Colorado, who helped conduct the experiments. Dr. Greenwood added that it was “not clear how that translates” into an exercise prescription for humans. We may require more weeks of working out, or maybe less. And no one has yet studied how intense the exercise needs to be. But the lesson, Dr. Greenwood says, is “don’t quit.” Keep running or cycling or swimming. (Animal experiments have focused exclusively on aerobic, endurance-type activities.) You may not feel a magical reduction of stress after your first jog, if you haven’t been exercising. But the molecular biochemical changes will begin, Dr. Greenwood says. And eventually, he says, they become “profound.”

09. November 2009 by Ruth Folger Weiss
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