Exercise makes sense, literally.  There is a growing body of evidence, from both human and animal studies, that routine aerobic exercise can boost brain power.  Cognitive decline was once thought to be inevitable as one aged.  Over recent years, however, investigators are discovering that regular exercise is associated with a reduced risk for and/or delayed onset of dementia in the aging population.  It appears that acquiring "brain fitness" is possible and is as important as achieving cardiovascular fitness for optimal health and well-being in the later years.

     According to Janet Fletcher Brady, M.S. Director of Medical Programs for LifeSpan (www.lifespanfitness.com), and cofounder/developer of Fitness Forever (www.fitnessforever.com/), "Age doesn't matter.  It is what you do as you age that has a big impact."  Living a healthy lifestyle overall, such as not smoking (smoking restricts blood flow and oxygen supply to the brain thereby impairing brain function), maintaining a healthy body weight, consuming a well-balanced diet that consists of antioxidant rich fruits and vegetables and foods rich in Omega 3's, engaging in intellectually challenging activities (crossword puzzles), and participating in regular physical activity preserve brain function.

     It has been long known and well established that routine exercise is good for the cardiovascular system and chronic disease prevention.  Now there is enough research to support its role in promoting brain health.  "What is good for the heart is great for the brain" states Brady.  "Exercise improves [blood] circulation which improves oxygen circulation, penetration, and pick-up at the cellular level" explains Brady.

     Starting around the third decade of life, decreases in the brain's gray and white matter occur which impair function and result in cognitive decline.  Age-related changes are greatest in the frontal, parietal, and temporal lobes of the brain.  These areas are responsible for the brain's "executive control."  "Executive control" refers to those tasks that entail complex thought and attention.  These areas of the brain function so that you can formulate plans of action, coordinate tasks, switch between tasks, disregard irrelevant information, and retain and process information over a short period of time (working memory).  Declines in the "executive control" processes of the brain threaten independent living in the later years.  Fortunately, research has found that these areas of the brain are spared the greatest as a function of aerobic fitness.

     A study on "Ageing, Fitness and Neurocognitive Function" conducted by Kramer et al. and published in the July 29, 1999 issue of Nature, found that aerobic training in previously inactive adults (ages 60-75 years) led to significant improvements in performance on tasks that relied on the "executive control" processes of the brain.  In another study, conducted by Colcombe et al. and published in The Journals of Gerontology Series A: Biological Sciences and Medical Sciences (58:M176-M180 [2003]), the researchers found that declines in brain tissue density were greatly reduced as a function of cardiovascular fitness when they assessed fitness levels of 55 adults (mean age 66.5 years) and compared their high-resolution magnetic resonance imaging brain scans.  In a subsequent study conducted by Colcombe et al., the investigators found that brain volume increased, particularly in the prefrontal and temporal areas of the brain (those most affected by age), as a result of aerobic fitness training.

     Researchers are still investigating the mechanism by which aerobic exercise leads to improvements in brain function in humans.  However, based on the findings of research conducted on animals, aerobic training appears to lead to the formation of new neurons (brain cells) and blood vessels as well as increases in the number of synaptic connections and levels of neurotransmitters and nerve growth factors.

     Although any form of aerobic activity is better than none, Brady explains that certain types of physical exercise are best for optimal "brain fitness."  First, exercises that incorporate cross-lateral movements (those that cross the midline of your body) are best.  These movements lead to an increase in blood flow to all areas of the brain and result in an increase in the number of synaptic connections formed in the brain.  Second, activities that include "cued-movements" (actions performed after being prompted by a signal or cue to move, such as with an instructor led aerobic dance class) are beneficial.  These help to focus attention.  Your mind needs to be actively engaged in order to retain information.  Brady also states that any physical activity that requires you to develop a new skill is important to enhance brain function.

     So what does this mean  for your exercise routine?  Brady says to "Exercise smarter.  Break-out, don't be repetitive.  Add brain-based activity that involves cross-lateral and cued-exercise movements to your routine."  If you are a runner, for example, add a few sessions per week of aerobic dance class or other exercises that incorporate the above brain boosting movements.  Following these recommendations will not only lead to a fit body, but a fit brain.

Note:  Before beginning an exercise program or increasing the intensity level of a current routine, a physician's approval should be obtained, especially for older adults and those at risk for or who currently have chronic health conditions.

Resources:

Phone Interview March 25, 2009 with Janet Fletcher Brady, M.S., Director of Medical Programs for LifeSpan (www.lifespanfitness.com); (www.fitnessforever.com/)

ACSM's Health & Fitness Journal March/April 2009 (13)2:27-31; "Exercising the Brain", Brady, J.

The Journals of Gerontology Series A: Biological Sciences and Medical Sciences 58:M176-M180 (2003) "Aerobic Fitness Reduces Brain Tissue Loss in Aging Humans", Colcombe, S.J. et al.

The Journals of Gerontology Series A: Biological Sciences and Medical Sciences 61:1166-1170 (2006) "Aerobic Exercise Training Increases Brain Volume in Aging Humans", Colcombe, S.J. et al.

Nature 400, 418-419 (29 July 1999) "Ageing, Fitness and Neurocognitive Function", Kramer, A.F. et al.

Proceedings of the National Academy of Sciences of the United States of America, 2004 March 2; 101(9): 3316-3321, "Cardiovascular Fitness, Cortical Plasticity, and Aging", Colcombe, S.J., et al.

"Nutrition and Brain Function: Food for the Aging Mind", USDA Agricultural Research Service (www.ars.usda.gov/is/AR/archive/aug07/aging0807.htm)