Wednesday, September 11, 2013

The Effects of Strength Training on Dementia Risk

Sometimes we're tied to the tracks when the train is coming through. There are some diseases we simply can't stop. When the warning signs are present, even the best intentions and actions can't prevent what's coming. However, similar to diabetes, dementia may not be one of those diseases. Research from the past three years indicates that strength training can reverse a strong risk factor for dementia.

These results are pertinent to health in the US. One in three US seniors have some form of dementia when passing. Over five million Americans have Alzheimer's disease, the most common form of dementia. Alzheimer's is also the sixth leading cause of death in the US.

The Specific Research Findings

Mild cognitive impairment (MCI) is a well-recognized risk factor for dementia. Researchers from the University of British Columbia said MCI "represents a critical window of opportunity for intervening and altering the trajectory of cognitive decline in seniors," [1].

The same researchers took a group of 70 to 80-year old women through a strength training program for six months. The participating women all were diagnosed with MCI after scoring low on a cognitive test. All participants also complained of memory issues as well.

The strength training program consisted of twice-weekly workouts, with each trainee performing 10 exercises, two sets each. The exercises were challenging, inducing complete exhaustion ("muscle failure") in about six to eight repetitions.

The women were scored on several cognitive tests before and after the six months of training. These tests included the Stroop Test (assessing selective attention, cognitive flexibility, and processing speed), Trail Marking Tests (speed at which a person can switch from one focused task to another), and Verbal Digit Span Tests (short-term memory). Functional MRIs were also conducted.

At the end of six months, the strength-trained women experienced the following gains:
  • Higher Stroop Test scores
  • Greater associative memory
  • Functional changes in three areas of the brain, meaning an increased blood flow was reaching these areas after six months
The study also included groups that participated in a relatively challenging walking routine or a mixture of stretching, relaxation, and balance exercises. Despite all three groups dedicating the same amount of time to their respective programs, strength training was the only intervention that produced cognitive improvements.

Conclusions and Other Populations

MCI is a significant predictor of dementia. However, a challenging strength training program reverses at least some of the MCI issues found in senior women. This change did not occur from the same amount of relatively fast-paced walking or a mix of low intensity activities.

What about mentally healthy populations? Treatments are always more likely to produce benefits in those who have more room to improve. In other words, a diet is more likely to produce weight loss in an obese person than a lean person.

In the next post, I will cover studies that examine the affect strength training has cognitively-healthy men and women. Until then, be good. Thanks for reading.

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