THE EXERCISE-BRAIN CONNECTION (from IDEA Fitness Journal, February 2012)
Did you know that your brain is incredibly dynamic? It can change its structure and function by adding new neurons, making new connections between neurons and even creating brand-new blood vessels, all in response to exercise.
Jeffrey A. Kleim, PhD, associate professor in the Arizona State University School of Biological and Health Systems Engineering, shares the following insights on how exercise impacts the brain.
Exercise Improves Cognitive Function – A sedentary lifestyle affects the brain—and in turn lessens mental capacity. One study found a clear connection between how much schoolchildren exercised and their cognitive performance: the more aerobic exercise the children engaged in, the better they performed on verbal, perceptual and mathematical tests.
The same pattern of results was found in older adults: aerobic training improved cognitive performance, and active lifestyles decreased age-related risks for cognitive impairment and dementia. Not surprisingly, these cognitive effects were accompanied by clear changes in brain structure and function.
Exercise Changes Brain Function – Research shows that exercise changes brain function in a lasting manner. For example, the reduced cognitive capacity in sedentary individuals is associated with different patterns of brain activity—both at rest and while performing mentally challenging tasks—than those observed in active subjects.
Plus, compared with sedentary people, active individuals show greater baseline levels of cortical activity. (The cerebral cortex helps with complex cognitive tasks.)
Exercise Changes Brain Structure – The structure of the brain can be broken down into two general components. Gray matter contains the neurons and supporting cells, while white matter consists of the axons of these neurons (nerve cell fibers) that carry signals from one area to another.
Magnetic resonance imaging (MRI) allows for the measurement of gray and white matter. MRI scans have shown that exercise boosts overall brain volume, increasing both gray matter and white matter. These changes can occur over relatively short periods of time. After learning to juggle for only a few weeks, for example, study subjects showed increases in gray matter within regions of the brain concerned with integrating visual and motor information.
Exercise Is Key To Lifelong Learning – The adult brain, especially the hippocampus, can continue to make new neurons throughout the lifespan. The hippocampus is concerned with forming memories and processing emotion, which may help explain some of the cognitive and emotional benefits of exercise. Interestingly, aerobic exercise can increase neurogenesis (generation of new neurons) within the hippocampus at many stages of development, including adult brains. The fact that the hippocampus is a critical brain structure used in memory may explain why aerobic exercise can enhance learning.
BONES AND SALT (from National Council on Strength & Fitness, June 2013)
A study presented at The Endocrine Society’s 95th Annual Meeting showed that a high-salt diet raises a woman’s risk of breaking a bone following menopause, no matter what her current bone mineral density (BMD) value is. This is particularly concerning as salt intake in the U.S. represents a 4-5 fold over-consumption value on a daily basis.
The study found that older women who consumed the highest quantity of sodium had more than four times the risk of suffering a non-vertebral fracture, even after adjustments for numerous additional variables that affect fracture risk. The lead author of the study states, “Excessive sodium intake appears to be a risk factor for bone fragility. It is therefore important to consider excessive sodium intake in dietary therapy for osteoporosis.” Non-vertebral fractures can cause substantial disability and even death (especially of the hip). Past research has shown a clear connection between excess sodium intake and decreased BMD.
The research team examined 213 post-menopausal women (average 63 years of age) who had previously undergone osteoporosis screening. The average daily sodium intake among the study participants was reported to be 5,211 mg, which is consistent with intakes in America. The group with the highest sodium intake consumed an average of 7,561 mg/day. This high-intake group was 400% more likely to have an existing non-vertebral fracture, compared with the lower-intake groups who did not experience an increased risk for fractures.
The average American consumes far more sodium than the RDA of 2,300 mg. The 2010 Dietary Guidelines for Americans further recommend that individuals over the age of 51 should not consume more than 1,500 mg of sodium/day. Older adults who are at risk for bone disease and hypertension must monitor salt intake. Consuming less processed foods, where sodium is widely used as a preservative and flavor-enhancer, helps to decrease the risk for debilitating fractures.