Alzheimer’s Disease: How Exercise and Sleep Can Protect the Brain
Nov 19, 2015
Here’s what you need to know:
- Alzheimer’s disease destroys the memory-forming structures in the brain (hippocampus). The major contributing factor is not genetics, but rather damage to the mitochondria of brain cells and chronic inflammation.
- Exercise generates a brain-protective chemical called brain-derived neurotrophic factor (BDNF.) And the right type of exercise produces larger amounts of BDNF.
- Sleep is essential, not only to repair the body, but to repair the brain as well.
Alzheimer’s is the sixth most common cause of death, but may actually be as high as the third most common cause, behind heart disease and cancer, due to inconsistencies in how cause-of-death is reported.
Alzheimer’s disease is not a normal part of aging. It is a progressive, degenerative disorder that attacks the brain’s nerve cells, or neurons, resulting in loss of memory, thinking and language skills, and behavioral changes. According to the Alzheimer’s Foundation of America, short-term memory fails when Alzheimer's disease first destroys nerve cells in the hippocampus, and language skills and judgment decline when neurons die in the cerebral cortex.
What’s Going on Up There?
The human brain uses massive amounts of energy. Wherever there is energy use, there is also the production of waste products. It is the ineffective handling of these waste products and poor lifestyle choices that are the major factors promoting the development of Alzheimer’s. This free radical and inflammatory damage to brain cells happens four ways:
- Reduction in energy supply, mostly due to free radical damage to the mitochondrial membrane
- Cumulative free-radical damage to lipids and proteins inside the cell, which turns them rancid
- Chronic inflammation in the brain, caused by free radical driven overexpression of the inflammatory cascade
- Free radical damage to mitochondrial DNA, which destroys bits of genetic code (Colgan, 2008)
There is hope, however. And it comes in the form of exercise and proper sleep (two treatments, which also happen to have many other pleasant side effects beyond brain health).
Get Your BDNF On!
Brain-derived neurotrophic factor (BDNF) is a protein produced inside nerve cells when they are active. It keeps neurons functioning and growing and also promotes growth of new neurons. You get a boost of BDNF from any physical activity, but you get an even bigger boost when you do the right kind of physical activity.
Physical Crossword Puzzles
When you perform physical activity that demands coordination beyond putting one foot in front of the other, you get a bigger boost of BDNF. One experiment showed that running rats had 35 percent less BDNF produced when compared to rats that were taught complex motor skills, such as walking across balance beams, unstable objects and elastic rope ladders (Greenough, 2004).
The point: Your workout regimen has to include skill acquisition and aerobic exercise. Essentially, you need to do physical crossword puzzles. Physical activity needs to be complex enough to involve problem-solving and movement. For some simple and fun ideas to implement this, check out, The Walking Games.
In summary: BDNF protects your brain. All exercise produces some BDNF, but mentally stimulating, engaging, skill-based physical activity produces much more BDNF than just walking or pedaling a stationary bike.
Flush Your Brain While You Sleep
Your brain may flush itself while you sleep. Sleep has already been shown to be essential and beneficial for a number of reasons. I’m sure you have experienced that feeling of being well-rested after a period of not being so—it may even feel like you’re on a performance-enhancing drug. Now, research has shown that the space between brain cells may increase during sleep, allowing the brain to flush out toxins that build up during waking hours. These results suggest a new role for sleep in health and disease (National Institutes of Health, 2013).
During sleep, a plumbing system called the glymphatic system may open, letting fluid flow rapidly through the brain. The glymphatic system helps control the flow of cerebrospinal fluid (CSF), a clear liquid surrounding the brain and spinal cord. Researchers found that the space inside the brains increased by 60 percent when the mice in the study were asleep or anesthetized.
Previous studies suggest that toxic molecules involved in neurodegenerative disorders accumulate in the space between brain cells. In this study, the researchers tested whether the glymphatic system controls this by injecting mice with labeled beta-amyloid, a protein associated with Alzheimer’s disease, and measuring how long it lasted in their brains when they were asleep or awake. Beta-amyloid disappeared faster in mice brains when the mice were asleep, suggesting sleep normally clears toxic molecules from the brain.
Not only do you maximize the repair of muscle tissue during sleep, it now appears to be essential for brain repair as well.
It’s no surprise that exercise and sleep are good for you. However, as brain science evolves and our understanding of how exercise and sleep protect the brain becomes more sophisticated, we can maximize the benefits of both by tailoring our time spent on both activities accordingly.
Alzheimer’s Association of America. (2015). About Alzheimer’s.
Colgan, M. (2008) Save Your Brain, Science Books. 2008.
Greenough, W. and Markham, J. (2004). Experience-driven brain plasticity: Beyond the synapse. Neuron Glia Biology, 1, 4, 351–363.
National Institutes of Health. (2013). National Institute of Neurological Disorders and Stroke (NINDS).