What impact does constant learning have on the brain?

Education is key to slowing brain aging. Simply put, the more you know, the more you stretch your brain's capacity for learning.

One of the better examples is a study of nuns in a monastery. The researchers analyzed the sentence structure of essays the nuns wrote before entering the convent, then looked into their cognitive function some 65 years later. Those who used the most complex sentence structure when they entered the convent had the highest cognitive function as they got older. (Here's another important finding: Those who were most optimistic in their entries also had higher cognitive function.)

Learning even helps if it's in a formal system. People with higher levels of education and those who continue to be involved in activities that stimulate the mind undergo less mental aging. A college graduate who also continues to learn in formal educational settings is 2.5 years younger than a high school dropout. But informal activity helps, too.

Keeping your mind active keeps arterial aging, immune aging, and even accidents in check and has a RealAge benefit of making you 1.3 years younger.