Those episodes of forgetfulness--the name you can't recall, the missing keys, the quart of milk you didn't buy--loom larger as you pass your fiftieth birthday.
The brain does change with age. Gradually, it begins to process information more slowly. You don't learn and retain new facts as well as you used to, and it takes longer to summon things out of the memory bank. This can be unsettling, but it is quite normal and does not usually signal the onset of disease.
In fact, it has been shown that the brain keeps making new cells, and connections among them, throughout life: retrieval from memory does slow, but the ability to learn is still there.
Dementia, including Alzheimer's disease, is not a normal part of aging, though the risk rises rapidly in the very old. Then there is the gray area known as mild cognitive impairment (MCI), which involves memory problems more severe than those seen with normal aging, but less severe than dementia; people with MCI can still do their daily activities on their own.
It's estimated that 20 percent of people over 70 have MCI, and about five percent of those with MCI progress to dementia each year, according to a recent British review of 15 long-term studies. But many people with MCI remain stable for years, and some actually improve, thanks to treatment of conditions that can impair memory and cognition, such as depression, hypothyroidism, or vitamin B12 deficiency.
Anyone who promises you guaranteed ways to protect and preserve your mind and prevent dementia is either trying to sell you something or suffering from wishful thinking. Still, scientists all over the world have been working to solve the mysteries of the aging brain.
Why do some people experience greater "cognitive decline" than others, and why do some develop dementia? Your genes clearly play a large role. One important thing researchers have learned is that what helps your cardiovascular system also seems to benefit your brain and helps protect it from disease.
Here's the latest thinking:
Research has consistently found that staying physically active is a key to preserving brain function. Studies have shown that older people who get regular exercise are less likely to decline mentally and/or develop dementia.
Aerobic exercise such as running or cycling seems especially beneficial, but any activity can help, including strength training and ballroom dancing (these two were the focus of recent studies). Exercise probably benefits the brain just as it helps the cardiovascular system--by lowering blood pressure, improving blood flow, controlling weight, and improving cholesterol levels and blood sugar. In addition, brain scans show that aerobic exercise can actually improve brain activity and produce new brain cells and connections between them.
Mental Activity and Lifelong Learning
Use it or lose it: the old adage also applies to mental ability. Read, take a class, work a puzzle, pursue an absorbing hobby--whatever makes you think. Exercising the brain can enrich your life, banish boredom, help treat depression, confer a sense of accomplishment, and be a way to make new friends--all good for mental health. A few recent studies on commercial "brain fitness" programs--including one in the Journal of the American Geriatrics Society in April--have yielded promising results, but usually the benefits are short-term and involve a limited set of mental skills.