View Full Version : Exercise helps to reduce stress it seems

11-18-2009, 12:51 PM

In the experiment, preliminary results of which were presented last month at the annual meeting of the Society for Neuroscience in Chicago, scientists allowed one group of rats to run. Another set of rodents was not allowed to exercise. Then all of the rats swam in cold water, which they don’t like to do. Afterward, the scientists examined the animals’ brains. They found that the stress of the swimming activated neurons in all of the ’ brains. (The researchers could tell which neurons were activated because the cells expressed specific genes in response to the stress.) But the youngest brain cells in the running rats, the cells that the scientists assumed were created by running, were less likely to express the genes. They generally remained quiet. The “cells born from running,” the researchers concluded, appeared to have been “specifically buffered from exposure to a stressful experience.” The rats had created, through running, a brain that seemed biochemically, molecularly, calm.

Cool stuff. More reason to exercise!

11-18-2009, 03:03 PM
This particular study has been examined in the scientific literature and is not all that well regarded. A large problem is that the "control" group was PREVENTED from moving about. This is a stressor that is certainly not comparable to a human's CHOICE not to exercise, and the restraint of the rats creates a stress that in itself may limit the plasicity and responsivity of the rats' central nervous system. So the control group is not really a control group at all but rather a group that was exposed to a stressor the other rats were not. Note also that the study refers to brains cells "created" during the experimental period. There is no clearly comparable phenomenon in humans, since you are born with all of your brain cells, though synaptic connections and dendrite pruning may occur. Properly done controlled studies in humans don't particularly support the notion that exercise somehow reduces vulnerability to stress. Most studies are either retrospective or lack proper control groups. The most recent studies concerning depression find no measurable benefit from exercise.