Exercise Reduces High Stress Levels, Shuts Off Excitement in Ventral Hippocampus

Exercise is an amazing thing. Not only can it help you lose weight, lower cholesterol levels and improve overall cardiovascular health, it can actually help your brain out under high levels of stress.

According to researchers at Princeton University, the brain reorganizes a response to stress that's more reduced and less pressured when regular physical activity plays a part of the daily routine.

The study watched mice who were exercised yet exposed to cold water as a stressor during the experiment. Their brains exhibited a spike in activity of neurons that shut off excitement in the ventral hippocampus, the region known to regulate anxiety.

Study author Elizabeth Gould, Princeton's Dorman T. Warren Professor of Psychology, notes that the impact of physical activity on the ventral hippocampus has not specifically been explored.

"Understanding how the brain regulates anxious behavior gives us potential clues about helping people with anxiety disorders. It also tells us something about how the brain modifies itself to respond optimally to its own environment," said Gould, according to a press release, who also is a professor in the Princeton Neuroscience Institute. 

During the experiments, mice were given unlimited access to a running wheel and the second group had no running wheel. Following a six week period, the mice were exposed to cold water for a brief period of time during the exercise periods.

The study notes that the brains of active and sedentary mice behaved differently almost as soon as the stressor occurred, according to an analysis. In the neurons of the sedentary mice, however, only the cold water spurred an increase in "immediate early genes" that rapidly turned on when a neuron fires. That lack of these genes in the neurons of active mice suggested that their brain cells did not immediately leap into an excited, nervous response.

The paper, "Physical Exercise Prevents Stress-Induced Activation of Granule Neurons and Enhances Local Inhibitory Mechanisms in the Dentate Gyrus," was published May 1 in the Journal of Neuroscience.