The Hormone That Stops Alzheimer’s

Athletes know that a vigorous workout can lead to “runner’s high.” This is a feeling of euphoria you get when exercise-activated brain chemicals boost your mood. For years, researchers attributed runner’s high to hormones called endorphins. But new research shows that exercise produces another hormone. It may have more profound effects than endorphins. It improves memory and may protect against Alzheimer’s disease. It’s called irisin . Our bodies release it into the bloodstream when we’re active. It seems to play a role in energy metabolism. But researchers have found it also promotes the growth of neurons in the hippocampus. That’s a region of the brain responsible for memory and learning. Dr. Ottavio Arancio is a researcher at Columbia University’s Vagelos College of Physicians and Surgeons and the Taub Institute for Research on Alzheimer’s Disease and the Aging Brain. He co-led the new study. [1] Dr. Arancio said research on irisin “may help explain why physical activity improves memory.” It may also point to why exercise “seems to play a protective role in brain disorders such as Alzheimer’s disease.” [2] The study was done in three parts: Scientists first examined tissue samples from brain banks. They found that levels of irisin in the hippocampus are lower in people with Alzheimer’s. The team then determined what irisin does to the brain. Experiments with mice showed that the hormone protects nerve connections and memory. When the scientists disabled irisin, brain synapses and memory suffered. When they boosted irisin levels, brain health markers improved. Lastly, the researchers analyzed how exercise affects irisin and the brain. They injected beta-amyloid into mice. Beta-amyloid is a protein that interferes with neurons and causes Alzheimer’s. They had the mice exercise by swimming almost every day for five weeks. Despite having the brain-damaging protein, the mice did not […]

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