Houston Methodist. Leading Medicine.
Houston Methodist. Leading Medicine

Nantz National Alzheimer Center

Exercise and Alzheimer's

Exercise improves your memory and could become a promising treatment for Alzheimer’s disease.

“You must exercise to improve your memory”

This was the main recommendation of the concluding lecture presented at the Inaugural International Symposium on Alzheimer’s disease organized by Dr. Gustavo Román, in Houston, Texas, on June 6, 2011.

Dr. Kenneth Rockwood, Professor of Geriatric Medicine and Neurology and Weldon Professor of Alzheimer Research at Dalhousie University in Halifax, Nova Scotia, Canada, reviewed the positive effects of exercise in the elderly and presented the promising results of the Canadian experience using exercise to improve cognitive function in the elderly. Professor Rockwood emphasized that vigorous exercise is needed. “Walking your dog at a leisurely pace has fewer benefits than a brisk walk that puts perspiration in your shirt,” he said. It has been known for some time that regular exercise lowers the possibility of developing Alzheimer’s disease; in comparison with seniors that do not exercise, those who exercise regularly lower the risk of developing Alzheimer’s by as much as 30%. Aerobic exercise improves the body’s motor function, auditory attention, memory, and executive function, i.e., the capacity of the brain to organize thought and action. Aerobic exercise increases cerebral blood flow, improves brain utilization of oxygen and glucose, and helps to eliminate biochemical waste and damaging free radicals.

Interestingly, exercise also stimulates the production of factors that promote neural growth, such as brain-derived neurotrophic factor (BDNF) and insulin-like growth factor (ILGF); as a result, interconnections between synapses likely increase and processing brain capacity improves. Moreover, exercise helps regulate chemical neurotransmitters in the brain increasing in particular dopamine and acetylcholine which are necessary to maintain nerve functions, mood, and cognition. Exercise increases brain cognitive reserve thereby reducing brain aging. Lastly, exercise improves psychological well-being, positive feelings, self-confidence, and improves the quality of sleep which is critical for normal cognitive functioning.

A research study published on February 15, 2011 in the prestigious journal Proceedings of the National Academy of Sciences of the USA and sponsored by the National Institute on Aging, National Institutes of Health (NIH), demonstrated that exercise training improves memory and increases the size of the hippocampus. The study was conducted at the Pittsburgh Claude D. Pepper Older Americans Independence Center and the University of Pittsburgh Alzheimer’s Disease Research Center.

The Hippocampus

The hippocampus (a part of the brain located under the temples) is considered to be the brain’s “memory bank” and is affected by aging and by Alzheimer’s disease. Progressive shrinking of the hippocampus with age can be measured with magnetic resonance imaging (MRI) of the brain. The Pittsburgh group demonstrated in a randomized controlled trial with 120 normal older adults, that aerobic exercise training increases by 2% the volume of the anterior hippocampus, leading to improvements in spatial memory. Exercise effectively reversed by 2 to 3 years the normal rate of hippocampal atrophy due to age.

Previous studies have shown that hippocampal volume increases with cognitive activity. For instance, a brain MRI study showed that the posterior hippocampus was significantly larger in licensed London taxi drivers, who have extensive navigation experience, compared with the hippocampus of inexperienced drivers.

Exercise & Your Brain

These studies demonstrate that it is possible to enlarge areas of the brain that are important for memory: The analogy comes to mind of bigger biceps muscles as a result of weight-lifting exercise. Clearly, the adult human brain has plasticity, i.e., the capacity for structural change in response to environmental demands. According to Professor Rockwood, the Canadian Study of Health and Aging evaluated the impact of exercise on health status and five-year survival of the elderly. About half of the participants exercised regularly and the rest had little or no exercise. Exercise was strongly associated with improving cognition and with lower mortality in late life. This study concluded that the net effect of exercise is to improve cognition, even with more people living longer.

Finally, a recent community-based exercise program of 4-month duration randomized in a controlled trial patients with Alzheimer’s disease and usual treatment with and without exercise. The group that exercised increased the Mini Mental State Examination scores by 2.6 points, had better mobility, and improved the Instrumental Activities of Daily Living scores by 1.6 points.

In conclusion, aerobic exercise appears to be an effective preventative intervention for dementia. Moreover, there is growing evidence that both aerobic and resistance training can help to maintain brain health in old age and perhaps improve cognitive function in Alzheimer’s disease.