Posted by JLx on August 19, 2007, at 9:53:43
Interesting article in the NY Times, "Lobes of Steel": http://www.nytimes.com/2007/08/19/sports/playmagazine/0819play-brain.html?ei=5070&em=&en=803d39a0393f3ad5&ex=1187668800&pagewanted=print
Excerpts:
"This spring, neuroscientists at Columbia University in New York City published a study in which a group of men and women, ranging in age from 21 to 45, began working out for one hour four times a week. After 12 weeks, the test subjects, predictably, became more fit. Their VO2 max, the standard measure of how much oxygen a person takes in while exercising, rose significantly.
But something else happened as a result of all those workouts: blood flowed at a much higher volume to a part of the brain responsible for neurogenesis. Functional M.R.I.’s showed that a portion of each person’s hippocampus received almost twice the blood volume as it did before. Scientists suspect that the blood pumping into that part of the brain was helping to produce fresh neurons. ...
The Columbia study suggests that shrinkage to parts of the hippocampus can be slowed via exercise. The subjects showed significant improvements in memory, as measured by a word-recall test. Those with the biggest increases in VO2 max had the best scores of all.
“It’s reasonable to infer, though we’re not yet certain, that neurogenesis was happening in the people’s hippocampi,” says Scott A. Small, an associate professor of neurology at Columbia and the senior author of the study, “and that working out was driving the neurogenesis.”
Other recent studies support this theory. At the University of Illinois at Urbana- Champaign, a group of elderly sedentary people were assigned to either an aerobic exercise program or a regimen of stretching. (The aerobic group walked for at least one hour three times a week.) After six months, their brains were scanned using an M.R.I. Those who had been doing aerobic exercise showed significant growth in several areas of the brain. These results raise the hope that the human brain has the capacity not only to produce new cells but also to add new blood vessels and strengthen neural connections, allowing young neurons to integrate themselves into the wider neural network. “The current findings are the first, to our knowledge, to confirm the benefits of exercise training on brain volume in aging humans,” the authors concluded.
And the benefits aren’t limited to adults. Other University of Illinois scientists have studied school-age children and found that those who have a higher level of aerobic fitness processed information more efficiently; they were quicker on a battery of computerized flashcard tests. The researchers also found that higher levels of aerobic fitness corresponded to better standardized test scores among a set of Illinois public school students. The scientists next plan to study how students’ scores change as their fitness improves. ...
Exercise speeds the brain’s production of serotonin, which could, in turn, prompt new neurons to grow. Abnormally low levels of serotonin have been associated with clinical depression, as has a strikingly shrunken hippocampus. Many antidepressant medications, like Prozac, increase the effectiveness of serotonin. Interestingly, these drugs take three to four weeks to begin working — about the same time required for new neurons to form and mature. Part of the reason these drugs are effective, then, could be that they’re increasing neurogenesis. “Just as exercise does,”Gage says. ...
This Is Your Brain on Something Other Than Exercise
The human brain undergoes neurogenesis — the creation of new cells — throughout a person’s life, although the amount depends on a variety of factors, not just exercise.
MARIJUANA: We just report the data; we don’t endorse it. A 2005 study on rats found that stimulation of the brain’s receptors for marijuana increased neurogenesis.
ALCOHOL: A 2005 study found that mice that swallowed a moderate amount of ethanol showed more neurogenesis than teetotalers. Other studies on mice have suggested that heavier drinking can be damaging to the brain.
SOCIABILITY: One study suggests that rats that live alone and have access to a run ning wheel experience less neurogenesis than those that have access to a running wheel and live in group housing. So go ahead and join that singles running club you’ve been avoiding.
DIET: A diet high in saturated fat and sugar sharply diminishes the brain’s production of the proteins and nerve-growth factors necessary for neurogenesis. Exercise may mitigate that effect somewhat.
STRESS: Mice that are subjected to uncontrollable stress (like electric shock) suffer substantial deterioration in their ability to produce new neurons.
CHOCOLATE: In a study published this year, an ingredient in cocoa, epicatechin, was shown to improve spatial memory in mice, especially among those that exercised. Epicatechin can also be found in grapes, blueberries and black tea. “I plan to start ingesting more epicatechin,” says Henriette van Praag, a neuroscientist at the Salk Institute, “as soon as I can’t find my car keys anymore.” "
I've never had a psychiatrist ask me what I habitually ate or whether I exercised, just, "What meds have you tried?"
I know from experience that I have less of a problem with depression when I exercise and eat more healthy.
Some people have said, however, that exercise makes them feel worse. Since there is a time requirement for neurogenesis apparently, I wonder if they just didn't stick with it long enough. Or perhaps it was too much, too soon? I just got done reading, "The Feel Good Diet" where Dr. Hart makes the point that too much exercise may be detrimental. Anything too strenuous and/or over 40 minutes, and/or that leaves you more hungry may be too much. (This was in reference to mood, stress, neurotransmitter depletion and the target audience of her book desiring to lose weight; obviously some people can exercise more without difficulty.)
I've increased my exercise some days and observed that paradoxically I had more trouble not overeating and felt more depressed. Now I know why. It's a case of "find the happy medium" apparently.
JL
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thread:777068
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