Here is a look at the many options people have for whipping their brains into shape:

Do aerobic exercise: This tops most lists of what scientists recommend for preserving brain cells. Aerobic exercise not only keeps the heart in shape, it also protects brain neurons by sending more blood to the brain to keep oxygen flowing.

Lose weight: One scary study found that people who are obese in middle age have twice the risk of developing dementia as those who maintain an ideal weight. Folks who have high blood pressure and high cholesterol also may be at higher risk of dementia, the Alzheimer’s Association reports.

Eat brain food: Chowing down foods rich in antioxidants helps because they cleanse the brain of so-called free radicals that corrode connections between brain neurons. Foods rich in antioxidants include leafy vegetables such as spinach, broccoli and cauliflower, and fresh fruit such as strawberries, cranberries and blueberries. Omega-3 fatty acids, found in cold-water fish such as salmon and trout, and in pills sold over the counter, also help fight brain decay.

Computer exercises: There are many options for brain training on computers. Here are a few programs developed by brain specialists:.

Brain Fitness, from Posit Science. This is sold mainly to retirement communities but is also available to individuals for $395. The program features listening exercises that attempt to help elderly people overcome the difficulty many develop in understanding words and phrases in conversation.

MindFit, by Cognifit, costs $129 and can be downloaded from www.cognifit.com. It features three types of exercises that the computer customizes to the user’s level of brain functioning.

Video games: Here are just two of the many video games aimed at tickling brain cells.

Nintendo is making a big move into brain fitness. Its Brain Age game, for $19, is played on the hand-held DS game system and offers exercises in math, drawing and reading aloud. Rather than keeping score, it gauges the speed and accuracy of players’ responses and calculates their “brain age,” which goes down as the player improves. Last year, Nintendo released a similar game for the DS, called Big Brain Academy, featuring challenges in logic, memory, math and analysis.

In July, Nintendo released a version for its Wii system, Big Brain Academy: Wii Degree. And in August, Nintendo rolled out Brain Age 2 for the DS, featuring mental puzzles and adding music and voice recognition.

Radica Brain Games, a handheld game from a Mattel subsidiary, is an option for people who don’t want to buy Nintendo’s DS player. Sold in Wal-Mart’s toy department for $20, it’s a standalone product requiring no special gaming system.

Online brain gyms: Web sites include HappyNeuron.com, MyBrainTrainer.com,