Tuesday, July 19, 2011

Want to keep your brainpower? Exercise, Hawai`i!

Hawai`i has among the most active citizens in the nation, but there's way more to do, according to a cluster of recent scientific and research reports.

The U.S. Centers for Disease Control reports all four counties in the Islands have among the lowest rates of physical inactivity in the nation.

Is there a benefit to that exercise? The CDC study says it's good for reduced diabetes risk, but new studies indicate it's also significant for a healthy brain.

Regular physical activity is linked to lower loss of cognitive function in older adults, according to two studies in Online First by Archives of Internal Medicine, a JAMA/Archives journal.

There has long been an association between exercise and good mental function, but much of the previous research has been based on self-reported data and thus questionable. The newest information addresses those shortfalls and still comes to a similar result.

In a French study, researchers followed a group of nearly 3,000 women with risk factors for heart disease, part of the Women's Antioxidant Cardiovascular Study. They found increased exercise resulted in reduced brainpower loss. The lead researcher was Marie-Noël Vercambre, of Foundation of Public Health, Mutuelle Generale de l'Education Nationale, Paris.

Briefly, the report found that something equivalent to a half-hour walk daily was associated with a statistically reduced risk of cognitive function loss.

"Various biologic mechanisms may explain the positive relation between physical activity and cognitive health," said Vercambre's group, in a press release from the Archives of Internal Medicine, of the Journal of the American Medical Association. "If confirmed in future studies, physical activity recommendations could yield substantial public health benefits given the growing number of older persons with vascular conditions and their high risk of cognitive impairment."

A second report looked at 197 participants averaging nearly 75 years of age in the Health, Aging and Body Composition study in Canada. Researchers were led by Laura E. Middleton, of the Heart and Stroke Foundation Centre for Stroke Recovery, Sunnybrook Research Institute, Toronto.

Interestingly, these researchers subtracted the individuals' resting metabolic rate from their total energy expenditure. They found that the participants who had the highest net energy expenditure tended to have the lowest cognitive loss.

"The mechanisms by which physical activity is related to late-life cognition are likely to be multifactorial,” Middleton's group said. "We are optimistic that even low-intensity activity of daily living may be protective against incident cognitive impairment."

Find the studies here: Arch Intern Med. Published July 19, 2011. doi:10.1001/archinternmed.2011.282; doi:10.1001/archinternmed.2011.277.

In an Alzheimer's study, exercise was listed as one of the keys to reducing the likelihood of suffering from the disease. A report in the journal Lancet said the key risk factors internationally for Alzheimer's disease are, in this order: low education, smoking, physical inactivity, depression, hypertension in midlife, diabetes and mid-life obesity. They are associated with half of all cases of Alzheirmer's.

Mental health researcher Deborah Barnes, of the San Francisco VA Medical Center, analyzed data from a massive pool of patients internationally—hundreds of thousands.

Among Americans, physical activity rises to the top as the biggest single modifiable risk factor listed in the study.

"What's exciting is that this suggests that some very simple lifestyle changes, such as increasing physical activity and quitting smoking, could have a tremendous impact on preventing Alzheimer's and other dementias in the United States and worldwide," said Barnes, who is also an associate professor of psychiatry at the University of California, San Francisco.

She had one caution about the research: "We are assuming that when you change the risk factor, then you change the risk," Barnes said. "What we need to do now is figure out whether that assumption is correct."

In the Islands, although we do well on the activity scale, we can do far better.

According to the state Department of Health's Hawai`i Physical Activity and Nutrition Plan:

“In 2005, almost 48 percent of adults in Hawaii did not meet the recommended guidelines for physical activity (moderate intensity physical activity for at least 30 minutes on five or more days of the week or vigorous intensity physical activity for 20 or more minutes on three or more days per week).”

© Jan TenBruggencate 2011

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