By growing new neurons, it seems the brain is another muscle that grows through exercise and fitness. Studies continue to reveal that not only are people who exercise better equipped to handle stress, they are also less likely to develop cognitive decline that comes with aging.
This is due to neuron development in the hippocampus, which is the area that regulates anxiety. People who exercise are more able to reorganize their brains to better handle stress, while those who do not exercise are less able to do so.
Researchers took two kinds of mice- active ones and lazy ones- and dumped them into cold water. The lazy ones had an increase in what were called "immediate early genes", which are genes that get turned on short term when a neuron is fired. The active mice didn't have these genes turned on, although they had more excitable neurons, due to more of a neurotransmitter known as GABA, which is known to keep the excitable parts of the brain in check.
This makes sense in the standpoint of "fight or flight" response. If your body is in shape as you experience stressful events, your brain will contain more GABA, which will keep you in a less anxious state, whereas if you are not in shape, you will have less GABA, which will force you to have to get up in the most intense anxious state in order to cope with stress. The reorganization of the brain's chemicals due to exercise allows for better regulation of anxiety leading to less stress and more relaxed response.
This is another negative impact of sedentary living. Sitting down all day at work or playing video games and being on computers all day not only leads to weight gain and declined physical health, but it also disables the brain from forming these natural feel good fight or flight response chemicals that enable it to handle stress better.
In addition, studies show that steady exercise improves overall general intelligence as well. This ability to regulate stress and distractions leads to an enhanced ability to focus on tasks, which is a component of overall intelligence.
This brings up the question: Is there a correlation between the decline in physical overall health caused by sedentary living and a decline in the population's general intelligence as well as student test scores?