Today's (Sunday) *Globe & Mail* includes an article: "Weight training and aerobic exercise linked to better brain health: study" by Gretcehn Reynolds.

Herre are some excerpts:

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Exercise is good for the brain. We know that. But most studies of exercise and brain health have focused on the effects of running, walking or other aerobic activities.

Now a new experiment suggests that light resistance training may also slow the age-related shrinking of some parts of our brains.

Our brains are, of course, dynamic organs, adding and shedding neurons and connections throughout our lifetimes. They remodel and repair themselves continually, in fact, in response to our lifestyles, including whether and how we exercise.

But they remain, like the rest of our bodies, vulnerable to time. Many neurological studies have found that by late middle age, most of us have begun developing age-related holes or lesions in our brains' white matter, which is the material that connects and passes messages among different brain regions.

These lesions are usually asymptomatic at first; they show up on brain scans before someone notices any waning of his or her memory or thinking skills. But the lesions can widen and multiply as years go by, shrinking our white matter and affecting our thinking. Neurological studies have found that older people with many lesions tend to have worse cognitive abilities than those whose white matter is relatively intact.

A few encouraging studies have suggested that regular, moderate aerobic exercise such as walking may slow the progression of white matter lesions in older people.

But Teresa Liu-Ambrose, a professor of physical therapy and director of the Aging, Mobility, and Cognitive Neuroscience Laboratory at the University of British Columbia in Vancouver, wondered whether other types of exercise would likewise be beneficial for white matter.

In particular, she was interested in weight training because it strengthens and builds muscles. Our muscles, like our brains, tend to shrink with age, affecting how we move. Punier muscle mass generally results in slower, more unsteady walking. More surprising, changes in gait with aging may indicate and even contribute to declines in brain health, including in our white matter, scientists think.

But, if so, Liu-Ambrose thought, then weight training, which strengthens and builds muscle, might be expected to alter that process and potentially keep aging brains and bodies healthier.

To test that idea, she and her colleagues turned to a large group of generally healthy women ages 65 to 75 who were already enrolled in a brain health study that she was leading. The women had had at least one brain scan. For the new study, published this fall in The Journal of the American Geriatrics Society, the scientists zeroed in on 54 of the women, whose scans showed existing white matter lesions.

The scientists tested the women's gait speed and stability, then randomly assigned them to one of three groups. Some began a supervised, once-weekly program of light upper- and lower-body weight training. A second group undertook the same weight-training routine but twice a week. And the third group, acting as a control, started a twice-weekly regimen of stretching and balance training. All of the women continued their assigned exercise routines for a year.

At the end of that time, their brains were scanned again and their walking ability reassessed.

The results were sobering and stirring. The women in the control group, who had concentrated on balance and flexibility, showed worrying progression in the number and size of the lesions in their white matter and in the slowing of their gaits. So did the women who had weight-trained once a week.

But those who had lifted weights twice a week displayed significantly less shrinkage and tattering of their white matter than the other women. Their lesions had grown and multiplied somewhat, but not nearly as much. They also walked more quickly and smoothly than the women in the other two groups.

These findings suggest that weight training can beneficially change the structure of the brain, but that "a minimum threshold of exercise needs to be achieved," Liu-Ambrose said. Visiting the gym once a week is probably insufficient. But twice a week may suffice.

<snip>

It may be that strengthened muscles release substances that migrate to the brain and stimulate beneficial changes there.

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The article is online at:
<http://bit.ly/KenPopeWtTrainingAerobicsBrainHealth>

Ken Pope