Who wants to live to be 100 if you can't remember your first love or the names of your grandchildren? A strong body is important, but a sharp mind is a key component to aging well.

To test your mental health, Dr. Oz and Dr. Roizen recommend an exercise that only takes 40 seconds.

Challenge your mind with this Brain Test worksheet.

"This test is a wonderful way of figuring out whether or not the circuitry of your brain is working," Dr. Oz says. "The brain is kept as alert as it is by an electrical grid. If you've got problems with the grid, if part of it goes down or you've got goop sapping up some of the power lines, which is what Alzheimer's is all about you're not going to be as quick."

Dr. Oz shares 15 ways to maintain your memory.

If you miss a few Hs, Dr. Oz says there's no need to panic. "You know you can turn your genes around. You know you can reverse aging," he says. "Now you have to turn the page, and figure out what to do about it. There's a lot we can do about mental health."