Physical Activity Improves Brain Health in those with Genetic Risk for Alzheimer’s Disease

by | Jan 12, 2016 | 2014, Alzheimer's Disease, Brain Health, Fitness and Exercise

Written by Greg Arnold, DC, CSCS. Individuals at high risk for Alzheimer’s and with low physical activity experienced a 3% decrease in the volume of their hippocampus.

Alzheimer’s disease is the most common form of dementia among older adults (1) and is the most significant contributor to the $215 billion that dementia costs our healthcare system each year (2). While 5.1 million Americans have Alzheimer’s, another 5.4 million are estimated to have cognitive impairment without dementia (3), totaling more than 10 million Americans with at least some form of cognitive impairment.

Research on preventing and slowing down symptoms of Alzheimer’s disease has focused on nutrition that includes 2,000 IU of vitamin E per day (4). Now a new study (5) suggests that physical activity can help maintain brain health in those genetically at risk for Alzheimer’s Disease.

Research has shown that people who have a gene called APOE-Epsilon4 have an increased risk for developing Alzheimer’s (6). MRI scans can show changes every 18 months in degeneration of the part of the brain that is the center of Alzheimer’s disease, the hippocampus (7). Building on these findings, researchers monitored 97 healthy subjects between the ages of 69 and 79 with no signs of Alzheimer’s Disease for 18 months, dividing them into 4 groups:

  • High Risk/High Physical Activity (22 patients): Those possessing the APOE-Epsilon4 gene and having high levels of physical activity
  • High Risk/Low Physical Activity (17 patients): Those possessing the APOE-Epsilon4 gene and having low levels of physical activity
  • Low Risk/Low Physical Activity (34 patients): Those not possessing the gene and having low levels of physical activity
  • Low Risk/High Physical Activity (24 patients): Those not possessing the APOE-Epsilon4 gene and having high levels of physical activity

Having “low” or “high” physical activity levels was established with the Stanford Brief Activity Survey (8). “Low” physical activity was defined as two or fewer days per week of low intensity physical activity (slow walking or light chores) and “high” physical activity included moderate to vigorous intensity activity 3 or more days per week (at least 15 minutes of brisk walking/jogging/swimming, moderately difficult chores for 45 minutes, at least 30 minutes of regular jogging, running, bicycling or swimming, or playing sports such as handball or tennis for an hour or more). MRI scans were taken before and after the study.

At the end of 18 months, those in the High Risk/Low Physical Activity group saw a 3% decrease in the volume of their hippocampus with no changes in the 3 other groups (p = 0.024). No other significant changes were seen in other regions of the brain for all of the groups.

While admitting the exact mechanism of how physical activity can help maintain hippocampus volume is not known, the researchers pointed to animal studies showing that physical activity:

  • Directly affects function of the APOE-Epsilon4 gene by means of nerve chemical receptors in the brain (called “cholinergic receptors”) as well as inflammation levels (9)
  • Increases blood flow in the brain that may affect the plaque formation (called “amyloid plaque”) that is the hallmark of Alzheimer’s Disease (10).

For the researchers, “These data suggest that individuals at genetic risk for Alzheimer’s Disease should be targeted for increased levels of physical activity as a means of reducing atrophy in a brain region critical for the formation of episodic memories.”

Greg Arnold is a Chiropractic Physician practicing in Hauppauge, NY.  You can contact Dr. Arnold directly by emailing him at PitchingDoc@msn.com or visiting his web site at www.PitchingDoc.com

Source: Smith, J. Carson, et al. “Physical activity reduces hippocampal atrophy in elders at genetic risk for Alzheimer’s disease.” Frontiers in aging neuroscience 6 (2014): 61.

© 2014 Smith, Nielson, Woodard, Seidenberg, Durgerian, Hazlett, Figueroa, Kandah, Kay, Matthews and Rao. Creative Commons Attribution License (CC BY).

Click here to read the full text study.

Posted May 22, 2014.

References:

  1. “NIH-supported study finds U.S. dementia care costs as high as $215 billion in 2010” posted on the National Institute of Aging website April 4, 2013
  2. “Prevalence of Alzheimer’s Disease” posted on the National Institute of Aging website
  3. Blassman PL. Prevalence of Cognitive Impairment without Dementia in the United States. Ann Intern Med. 2008 March 18; 148(6): 427–434
  4. Dysken MW. Effect of vitamin E and memantine on functional decline in Alzheimer disease: the TEAM-AD VA cooperative randomized trial. JAMA. 2014 Jan 1;311(1):33-44. doi: 10.1001/jama.2013.282834
  5. Carson Smith J.  Physical activity reduces hippocampal atrophy in elders at genetic risk for Alzheimer’s disease.  Front Aging Neurosci 2014 Apr 23;6:61. doi: 10.3389/fnagi.2014.00061. eCollection 2014
  6. Bird,T.D.(2008).GeneticaspectsofAlzheimerdisease. Genet.Med. 10, 231–239. doi: 10.1097/GIM.0b013e31816b64dc
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  8. Taylor-Piliae RE. Clinical utility of the Stanford brief activity survey in men and women with early-onset coronary artery disease. J. Cardiopulm. Rehabil.Prev 2007; 27: 0227–232.doi:10.1097/01.HCR.0000281768.97899.bb
  9. Intlekofer K.  Exercise counteracts declining hippocampal function in aging and Alzheimer’s disease. Neurobiol.Dis 2012; 57: 47–55. doi: 10.1016/j.nbd.2012.06.011
  10. Head D. Exercise engagement as a moderator of the effects of APOE genotype on amyloid deposition. Arch.Neurol 2012; 69: 636–643.doi:10.1001/arch- neurol.2011.845