As many people age, their brain loses its edge, its memory, and its willingness to learn, grow and engage in new adventures. It loses "neuroplasticity," which is the ability of nerve cells to be flexible and adaptive.

As many people age, their brain loses its edge, its memory, and its willingness to learn, grow and engage in new adventures. It loses "neuroplasticity," which is the ability of nerve cells to be flexible and adaptive.

The good news is this doesn't have to happen. With proper stimulation, exercise, diet, sleep and — that much overlooked element, water — your brain can keep ticking along in your older years, even if it does lose some of its flexibility.

"What we're finding out is you absolutely have the ability to do what you want to do in your life, to remember, to say what you want to say, to express yourself and be fulfilled, instead of declining into confusion, poor memory and inability to respond," says "Brain Fitness" teacher Lorraine Jarvi of Relationships First in Medford.

While teaching a class at Providence Medford Medical Center recently, Jarvi emphasizes that we live in a world full of stress and toxins that deprive us of time, decent diet, sleep and the inner peace and strength we need to keep our brains on track.

It's well known that, to keep all our marbles, we have to keep stimulating the mind with new learning experiences, such as chess, crossword puzzles, or learning a craft, language or musical instrument. But, says Jarvi, studies are now showing that you can't just learn these things, you have to take them out in the world, talk about them, share them and put them to use in some meaningful way.

Simplest is to engage in a lot of reading, but then be sure to discuss it with others, so you're thinking about it, building on it and using it, says Rawland Glass, director of Relationships First. The corollary to this is to cut way down on TV, "which is a state of not using your brain. You're letting someone else tell you what to think. It kills creativity and doesn't stimulate brain cells."

When reading, don't treat the book like a paper TV, but rather challenge yourself by making a guess at what's going to happen next, write a review of it for publication on some Internet blog or start a book-discussion group, says Jarvi. If the book is nonfiction, put it to work by teaching a class on it or, if it's history, go study the actual site in person.

If reading is stimulating, writing is stimulation tenfold. Jarvi says keep a journal, challenging yourself to explore complex topics or current events. Also, write your memoirs, which stimulates the vital part of your brain used for memory — and it's guaranteed to have interested readers at some point down the road.

Joe Shelton, 69, of Medford, came to the class "because I don't want to be senile when I get old. I take Spanish and it helps. I'm active in clubs that stimulate the mind, such as the Native Plant Society and the Rock Garden Society — and if the TV is on, it's about nature, documentaries and astronomy."

Gordon Larum, 81, of Medford, was drawn to Brain Fitness, he says, from a desire to limit the seemingly inevitable effects of aging on the mind. His strategies? He does the crossword puzzle in the Mail Tribune most days, reads in Spanish and German, and he follows a good diet, with occasional fish and fowl, no red meat.

Diet is a biggie for brain cells, says Glass. You have to work to avoid the typical diet of processed foods and look instead for lots of fresh, organic vegetables and fruits, plenty of them raw, with minimal meat.

Getting enough sleep and drinking plenty of water may seem like bothers you can brush off and catch up on later. But, says Jarvi, losing even a little sleep impairs thinking, reaction time, memory, new ideas, planning, time sense, dealing with unfamiliar situations, expressing yourself, keeping emotions stable, and immunity.

If you're not scared yet, here is another sleep tip: You need the two hours before midnight for restoration of the prefrontal cortex. That's the hardest-working part of the brain and is used for organizing, planning and retrieving memories.

You need two quarts of water a day for optimal brain function; that's because the gray matter is the thirstiest organ in your body and is actually made up of more water than any other part of your body, says Jarvi. Water is brain food.

Brain fitness requires discipline, but it pays off big time, says Jarvi, citing a study of 678 nuns over the past two decades. All of them were on the same diet and routines, but that the ones who upped their cognitive ability by one point on a five-point scale had a 33-percent drop in Alzheimer's.

Good, loving relationships, with plenty of calm and respect — but also the ability to process through resentments — are vital to positive brain functioning.

"Unexpressed resentments," says Glass, "are one of the biggest killers of brain cells."

John Darling is a freelance writer living in Ashland. E-mail him at jdarling@jeffnet.org.