From this New York Magazine article Why Running Helps Clear Your Mind -- Science of Us:
A New York times article asks Do the Brain Benefits of Exercise Last? In a word, no. It appears that desirable changes are not permanent, much like when a person stops exercising the body reverts to its former de-conditioned state.
Experimenters took two groups of rats, one group exercised on a treadmill and the other did not exercise. Afterward, the researchers
compared the animals’ performance on the memory test, as well as the number of new brain cells in the hippocampus of each group of rats.
They found that:
”The rats that had run were much faster on the water maze test than the control animals. They also had at least twice as many newborn neurons in the hippocampus.
But those advantages faded after several more weeks of not running. The brains of the animals that had been inactive for three weeks contained far fewer newborn neurons than the brains of the animals that had rested for only one week. The brains of the animals that had been inactive for six weeks had fewer still”.
In a study two groups took a memory quiz. Then one group cycled to exhaustion in 30 minutes and the other group sat there. Their memories were then retested. The result:
“The exercised volunteers performed significantly better on the memory test than they had on their first try, while the volunteers who had rested did not
improve” – quote from the NY Times article How Exercise Benefits The Brain.
They also took blood samples throughout the experiment. They found that: “The cyclists had significantly higher levels of a protein known as brain-derived neurotrophic factor, or BDNF, which is known to promote the health of nerve cells. The men who had sat quietly showed no comparable change in BDNF levels.”
From the article Get Moving for a Health Brain in the September 2013 AARP Bulletin these quotes:
The latest research shows that cognitive decline is not inevitable…the brain continues to make new neurons and fine tune neural connections as we live…Aerobic exercise jumps-tarts that process and slashes your lifetime risk of Alzheimer’s’ in half and general dementia by 60 %.
Exercise boosts the flow of blood to the brain, spurring the release of what has been dubbed Miracle-Gro for the brain – brain-derived neurotrophic factor (BDNF). This chemical stimulates the formation of new neurons in the hippocampus, the area involved in memory, learning and the ability to plan and make decisions. BDNF also repairs cell damage and strengthens
From this study, Effects of aerobic exercise on mild cognitive impairment: a controlled trial this quote:
“Six months of high-intensity aerobic exercise had sex-specific effects on cognition… aerobic exercise improved performance on multiple tests of executive function, increased glucose disposal during the metabolic clamp, and reduced fasting plasma levels of insulin, cortisol, and brain-derived neurotrophic factor.”
The sixteen men in the study did not achieve the same positive cognitive results. They postulated that the difference was possibly because the body's use of and production of cortisol, insulin, and glucose differed in women and men. Regardless, the long list of positive changes resulting for high intensity exercise makes it worth the investment of one’s time.
“There’s a lot of hype in this field in terms of brain improvement. I did set out to find out what actually works and what we know. What we do with our bodies has a huge impact on our brains. Our brains are more like our hearts in that everything you do for your heart is thought to be equally as good or better for your brain. Exercise is the best studied thing you can do to your brain. It increases brain volume, produces new baby brain cells in grownup brains. Even when our muscles contract, it produces growth chemicals. Using your body can help your brain.” From the NYT article, The Talents of a Middle-Aged Brain.
A strong body and a strong mind can be obtained through exercise. Prior blog entries dealing with cognitive decline and exercise:
From this article Good Diets Fight Bad Alzheimer Genes:
The researchers are exhilarated to find that a diet high in Omega 3 oils and low in cholesterol appears to significantly reduce the negative effects of the APOE4 gene in mouse models.
The APOE4 gene is a known risk factor for Alzheimer's and is present in 50% of all Alzheimer's patients.
The main take-away message here is that good diets can alleviate the effects of bad genes. Of course nutritionists have had this general idea for a while, but it's nice to be able to show that this approach can be applied to specifically counteract the negative effects of Alzheimer's disease-related genes,"
A NYT article Taking Early Retirement May Retire Memory, Too reports on a study by two economists that shows that in countries where people work longer people have sharper memories. See the graph.
While the study is not conclusive it does point to an interesting result. If causation is established rather than just correlation it would be important to know what aspect of work is producing cognitive longevity. A quote from the article:
"If work does help maintain cognitive functioning, it will be important to find out what aspect of work is doing that, Dr. Suzman said. “Is it the social engagement and interaction or the cognitive component of work, or is it the aerobic component of work?” he asked. “Or is it the absence of what happens when you retire, which could be increased TV watching?”