RIO DE JANEIRO, Jan. 7 (Xinhua) -- Physical exercise can counter the loss of memory caused by Alzheimer's, according to a study published Monday in the magazine "Nature Medicine."
Researchers at the Federal University of Rio de Janeiro (UFRJ), working with other universities and institutes, succeeded in establishing a link between levels of irisin, a hormone produced by the body during exercise, and the development of the progressive disease.
The tests, carried out on rats with Alzheimer's, showed low levels of irisin in the brains of Alzheimer's sufferers, and a reversal in memory loss when irisin levels were boosted through physical exercise.
UFRJ professor and an author of the study Sergio Ferreira said the great contribution of the study was to show that "the levels of this hormone are in fact decreased in the brains of patients with Alzheimer's."
Additionally, researchers showed that by boosting the levels of the hormone, "memory improves," he said.
By showing that "irisin is an important mediator of the beneficial effects of exercise," the findings indicate the hormone can be "a novel agent capable of opposing synapse failure and memory impairment," the magazine said on its website.
UFRJ researcher Mychael Lourenco said the findings reinforce the importance of physical activity in preventing memory loss and brain diseases, including Alzheimer's.
Such studies began seven years ago, after a Harvard researcher said irisin alleviated the symptoms of type 2 diabetes in rats, launching research to determine whether the hormone could have a protective effect on the brain.
Alzheimer's is a degenerative disease that erodes memory, eventually impairing language, reasoning and other mental functions.