How to fundamentally remodel your brain…
So the scientists next gently placed the remaining mice in ice-cold water for five minutes. Mice do not enjoy cold water. They find immersion stressful and anxiety-inducing, although it is not life-threatening.
Then the scientists checked these animals’ brains. They were looking for markers, known as immediate early genes, that indicate a neuron has recently fired.
They found them, in profusion. In both the physically fit and the sedentary mice, large numbers of the excitable cells had fired in response to the cold bath. Emotionally, the animals had become fired up by the stress.
But with the runners, it didn’t last long. Their brains, unlike those of the sedentary animals, showed evidence that the shushing neurons also had been activated in large numbers, releasing GABA, calming the excitable neurons’ activity and presumably keeping unnecessary anxiety at bay.
In effect, the runners’ brains had responded to the relatively minor stress of a cold bath with a quick rush of worry and a concomitant, overarching calm.
What all of this suggests, says Elizabeth Gould, director of the Gould Lab at Princeton, who wrote the paper with her graduate student Timothy Schoenfeld, now at the National Institute of Mental Health, and others, “is that the hippocampus of runners is vastly different from that of sedentary animals. Not only are there more excitatory neurons and more excitatory synapses, but the inhibitory neurons are more likely to become activated, presumably to dampen the excitatory neurons, in response to stress.”
We’ve known for years that athletes can survive stress and damage that would easily kill most people. Now, we know why…