The Brain's 'Alternative Energy' During Exercise

[RobinN]

Alternative energy is all the rage in major media headlines, but for the human brain, this is old news. According to a study by researchers from Denmark and The Netherlands published in the October 2008 print issue of The FASEB Journal, the brain, just like muscles, works harder during strenuous exercise and is fueled by lactate, rather than glucose. Not only does this finding help explain why the brain is able to work properly when the body’s demands for fuel and oxygen are highest, but it goes a step further to show that the brain actually shifts into a higher gear in terms of activity. This opens doors to entirely new areas of brain research related to understanding lactate’s specific neurological effects.

“Now that we know the brain can run on lactate, so to speak, future studies should show us when to use lactate as part of a treatment,” said Gerald Weissmann, MD, Editor-in-Chief of The FASEB Journal. “From an evolutionary perspective, the result of this study is a no-brainer. Imagine what could have or did happen to all of the organisms that lost their wits along with their glucose when running from predators. They were obviously a light snack for the animals able to use lactate.”

To reach their conclusion, the researchers looked at research that compared the blood running to and from the heads of volunteers undergoing strenuous exercise. They found that the blood on its way to the brain contained considerably more lactate than blood flowing from the brain. Further investigation showed that the brain was not storing the lactate which had come from the muscles during exercise, but rather using it as fuel. In fact, the brain helped to clear lactate from the circulation, thereby leaving glucose to the muscles that need it for the hard work they were performing.

The FASEB Journal (http://www.fasebj.org) is published by the Federation of American Societies for Experimental Biology (FASEB) and is the most cited biology journal worldwide according to the Institute for Scientific Information. FASEB comprises 21 nonprofit societies with more than 80,000 members, making it the largest coalition of biomedical research associations in the United States. FASEB advances biological science through collaborative advocacy for research policies that promote scientific progress and education and lead to improvements in human health.

Article Details: Bjørn Quistorff, Niels H. Secher, and Johannes J. Van Lieshout. Lactate fuels the human brain during exercise. FASEB J. 2008 22: 3443-3449. Visit http://www.fasebj.org/cgi/content/abstract/22/10/3443 to view the article.

Source: Cody Mooneyhan
Federation of American Societies for Experimental Biology

http://www.zampbioworld.org/bionews/index.php/2008/10/01/8030

 

[Bernard]

Interesting. I'm not sure what ramifications it has vis a vis epilepsy though.

 

[RobinN]

When cellular oxygen levels are decreased, however, and/or the mitochondria are not functioning properly, the body must turn to less efficient anaerobic energy production to metabolize glucose and produce ATP. In this process, the primary byproduct is

lactic acid, which can build up faster than the liver can break it down

. When lactic acid levels increase significantly in the blood, the affected person is said to have first hyperlactatemia and then lactic acidosis (LA). The body can often compensate for the effects of hyperlactatemia, but LA can be severe enough to disrupt a person’s acid/base (pH) balance and cause symptoms such as muscular weakness, rapid breathing, nausea, vomiting, sweating, and even coma.

Lactic acidosis is separated into two types: A and B. Type A may be due to inadequate oxygen uptake in the lungs and/or to decreased blood flow (hypoperfusion) resulting in decreased transport of oxygen to the tissues. The most common reason for this is shock from a variety of causes including trauma and blood loss, but LA may also be due to conditions such as heart attack, congestive heart failure, and pulmonary edema (fluid in the lungs). Type B is caused by conditions that increase the amount of lactate/lactic acid in the blood but are not related to a decreased availability of oxygen. This includes liver and kidney disease, diabetes, leukemia, AIDS, glycogen storage diseases (such as glucose-6-phosphatase deficiency), drugs and toxins, severe infections (both systemic sepsis and meningitis), and a variety of inherited metabolic and mitochondrial diseases (forms of muscular dystrophy that affect normal ATP production). Strenuous exercise can also result in increased blood levels of lactate.

http://labtestsonline.org/understanding/analytes/lactate/sample.html

Mitochondria are components of cells that are involved in metabolism and enzyme production. They are the energy factories of our cells. They also contain genetic material. Particular abnormalities in the mitochondrial genes are often associated with epileptic disorders. The metabolic disorders involving the mitochondria affect different parts of the body, including muscle and brain.

Mitochondria are inherited through the mother. Two mitochondrial disorders are often associated with epileptic seizures:
MELAS

One is MELAS: mitochondrial myopathy, encephalopathy, lactic acidosis (meaning too much lactic acid in the blood), and strokelike episodes. MELAS can lead to strokelike episodes at a young age (usually before 40), seizures, dementia, headaches, vomiting, unsteadiness, and ill effects from exercise. Persons with MELAS can have both generalized seizures (including myoclonic and tonic-clonic) and partial seizures.

http://www.epilepsy.com/epilepsy/epilepsy_mitochondrial