It has long been established that regular, challenging activity can stave off the degenerative brain changes associated with Alzheimer's. Although many people dream of working hard in their youth and retiring early, a new, surprising study has suggested that working longer into one's senior years may help to reduce the risk of developing dementia.

"Use it or lose it," is probably true.

A 2013 mental health study conducted by the French government noted an inverse correlation between career length and frequency of dementia diagnoses. The longer a person works, the lower the chance of developing dementia.

INSERM (the French equivalent of our National Institutes of Health) surveyed nearly half million older adults and found that the risk of developing Alzheimer's or similar cognitive dysfunction was reduced by an average of 3.2 percent per year worked after the age of 60. So, a person who retires at 65 would be expected to have reduced his or her chances of getting Alzheimer's by about 15%.

Working requires a high degree of mental engagement. Regular social interaction, physical activity and problem-solving are all essential for maintaining brain fitness. It follows then that working, which requires all of the above, may help to delay degenerative cognitive change. In effect, if you are using your brain, you are helping yourself not to lose it.

No one is suggesting you shouldn't retire.

With modern medicine extending vitality and life expectancy, many people are now working longer into their golden years, but not everyone has the option of putting off retirement. After all, a lifelong brick mason can't expect to be able to climb scaffolds and carry mortar well into his 70s or 80s. A 65-year-old with a serious heart condition probably shouldn't continue working in a high-stress job.

But the good news is that working isn't the only way to engage your brain.

Though the French study focused on length of career versus dementia frequency, the findings lent general support to the hypothesis that any mental activity is good for you. There are many things a person can do to stay active if he or she is no longer working:

• Take a lifelong learning course at your local university. Many colleges offer reduced, or even free, tuition for seniors.
• Get involved in a volunteer organization. Consider participating in Kiwanis, Junior League, the International Order of Odd Fellows, or other service group. You'll have fun, meet new people and help to better your community.
• Join a social club. The Red Hat Society, senior citizen travel groups and other clubs are a fun way to get out of the house and stay vital.

If health concerns keep you from getting out and about, challenge your mind at home.

There are plenty of ways to keep your brain engaged from the comfort of your living room. The more you push the sundry parts of your mind, the more you can do to maintain brain fitness.  Remember, though, that different parts of your mind process different stimuli, so vary the types of activities you engage in.

• Solve puzzles. By doing a daily sudoku, crossword or word search, you'll engage the neocortex of the brain, which processes logic and abstract thought. Jigsaw puzzles will help to stimulate areas which are responsible for understanding spatial relationships.
• Listen to music. Many studies have show that listening to music improves memory. This makes sense, as both hearing and memory are processed in the temporal lobe.
• Write. The physical act of writing requires coordination and fine motor skill; from a cognition standpoint, it stimulates logic, reasoning and memory. Writing letters, or even your memoirs, is an excellent way to engage the outside world while keeping your inner world healthy and balanced.

When it is time for you to stop working, consider moving to a retirement community.

Senior centers aren't just for the infirm.

Retirement living in the right community can be a rewarding experience and an excellent way to stay active. It can provide you an opportunity to meet new faces and participate in social activities with peers in your own age group.

Talk to your loved ones about your plans for retirement living. Scout out senior communities in your area and determine in advance which feels like the best fit for you, so that when you and your family decide it is time to take the next step, you'll be ready.