MADISON, Wis. -- Many people spend time exercising their bodies, but they might not be so diligent about exercising their brains.

In part three of WISC-TV's "Exercising Your Brain" series, we take a look at how technology can help keep minds sharp.

"As you do certain math and word problems, it increases blood flow to the brain and what it does is helps your brain workout," said Reggie Fils-Aime, executive vice president of sales and marketing for Nintendo.

Nintendo just launched a line of video games aimed at helping brains work.

One is called Brain Age and the other is the Big Brain Academy. In Brain Age, people are given 11 different tasks to strengthen their mind. Then they are administered a test to find out how old their brain is.

The idea is to do the tasks on a daily basis and take the brain age test once each day. The goal is to have your brain age rating decrease.

In Big Brain Academy, players are given 60 seconds to finish as many math, analytical and other problems as possible, and then the players' strengths are plotted. Gamers find out how much their brains weigh and try to make them heavier as they take the tests.

"Research shows maintaining an active lifestyle is done by being physically and mentally active," said Dr. Elizabeth Zelinski, of the USC Gerontology School.

Since launching the Nintendo DS and DS Lite, 21 million systems have been sold worldwide. The Brain Age game sold 2 million copies in Japan and hundreds of thousands of copies in the United States.

Brain Age and the Big Brain Academy carry a special G-Touch Generation logo meaning it's meant for all ages, even those who've never played a video game before.

The DS Lite retails for $129 and the Brain Age game itself retails for $20.