Surely someone has told you that they enjoy running because it allows them to disconnect. And you may even feel that way yourself. Recent research with mice suggests that there may actually be a scientific basis for this claim, since brain activity actually declines when performing a simple and repetitive action.
Being awake and asleep are not two exclusive and uniform states. Sometimes the boundary between the two can be somewhat diffuse. Our normal behavior, such as the ability to react quickly to unexpected events, deteriorates as we stay awake beyond our usual bedtime. Researchers are not quite sure why, but they suggest it may be because parts of our brain go to sleep without warning, even when we are technically awake. But with the right motivation, we can also force our prized organ to stay awake and even restore our performance in the usual way.
The time we need to sleep or stay awake depends largely on our genes, but the evidence suggests that they are also affected by the activities we do while we are awake. Previous studies believe that sleep does not start in the entire brain at the same time, but in the local networks of neurons that we use most when we are awake.
To test this theory, they resorted to mice, which they ran on a wheel for miles for several nights. When the mice ran this way, they spent far more deserts, as if their need for sleep was accumulating at a slower rate or something invalidated. To shed some light on this mysterious process, researchers tried to determine what was happening in their brains as they ran spontaneously.
To do this, they recorded the electrical activity of their nerve cells located in the neocortex as they ran on that wheel. Usually, when a mouse (or a human) is awake and active, its neurons were activated quickly. This is because the brain must be aware of several things: monitor the environment, coordinate movements and make decisions immediately. This activity requires a lot of energy, about 20% of all that our body uses.
Surprisingly, researchers observed that when the mice ran at high speed, some of their neurons stopped working altogether. The overall activity of the brain responsible for the motor and sensory areas also decreased by at least 30%. Paradoxically, this suggests that, in general, active physical behavior and intense movement do not necessarily require a more active brain.
