Your brain is a tissue and so like any other tissue, abuse, lack of use, and especially age causes its performance to decline. Sometime in our late twenties the hippocampus, the portion of our brains devoted to learning and memory, loses about a percent per year in total volume. So it's no surprise that as we get older we naturally lose some of our memory and learning capacity.
El ejercicio fisico te hace mas inteligente:
Brain cells can improve intellect only if they join the existing neural network, and many do not, instead rattling aimlessly around in the brain for a while before dying. One way to pull neurons into the network, however, is to learn something. In a 2007 study, new brain cells in mice became looped into the animals' neural networks if the mice learned to navigate a water maze, a task that is cognitively but not physically taxing. But these brain cells were very limited in what they could do.
When the researchers studied brain activity afterward, they found that the newly wired cells fired only when the animals navigated the maze again, not when they practiced other cognitive tasks. The learning encoded in those cells did not transfer to other types of rodent thinking. Exercise, on the other hand, seems to make neurons nimble. When researchers in a separate study had mice run, the animals' brains readily wired many new neurons into the neural network. But those neurons didn't fire later only during running. They also lighted up when the animals practiced cognitive skills, like exploring unfamiliar environments. In the mice, running, unlike learning, had created brain cells that could multitask.
Most studies have focused on aerobic activities like running or swimming. But even walking can make a difference. One study showed that older people who walked for just 40 minutes three days a week took two years off the "age" of their hippocampus—and improved their memory function.
Fuente: http://www.nytimes.com/2012/04/22/magaz ... -brain.htm
Fuente: https://www.linkedin.com/pulse/really-e ... jeff-haden
Nota: Al menos el ejercicio es beneficioso para los que no somos como Llinares!