Keep exercising!

I have always worried that aging is associated with declining mental functions, apparently regular exercise can help reverse the atrophy. That is the reason that I will keep playing tennis and trying to walk regularly among other sports.
Neurologists have long known that the our brains get slightly smaller as we grow older and that this shrinkage is associated with a gradual decline in certain mental functions. Previous research has demonstrated that regular exercise can slow the pace of shrinkage and help protect memories and preserve the ability to learn new things.
Now a new study suggests that even starting an exercise program later in life can undo some of the brain shrinkage in seniors who've spent years as a couch potatoes.
"Our results show we can reverse the atrophy that was already taking place," said the lead researcher, Kirk Erickson of the University of Pittsburgh.
For the study, they recruited 120 healthy but sedentary volunteers ranging in age from 60 to 80. (None had been diagnosed with dementia or were suspected of having Alzheimer's disease.)
Half of the seniors were given an aerobic exercise regimen of walking around a track for 40 minutes a day, three days a week.
The other half served as a control group. They were told to do stretching and toning exercises activities that would barely budge their heart rates.
Each participant underwent a series of MRI scans to measure changes in the size of the hippocampus, the brain structure involved in all form of memory formation.
The findings, published in the Proceedings of the National Academy of Sciences, revealed a dramatic difference in the two groups after one year. The walkers experienced increases in the volume of the left and right hippocampus by 2/12 and 1.97 per cent respectively. The same regions of the brain in those who did stretching decreased by 1.40 and 1/43 per cent respectively, which amounts to the normal expected shrinkage.
"You can think of the increase in volume of the hippocampus as turning back the clock by almost two years."explained the senior author of the study, Art Kramer of the University of Illinois.
Furthermore, the bigger brains seemed to work better.
I am convinced, keep exercising.