Sometimes data behaves so nicely, lining up just the way you want it to. In 2012, irisin was identified as a molecular messenger induced by exercise. In 2013, irisin was found to stimulate genes in the hippocampus, a region of the brain essential for making and storing memories. In 2017, epidemiological studies indicated that exercise could slow the development of Alzheimer’s disease (AD) and other kinds of dementia. And this week—you guessed it—new research demonstrated that exercise alleviates AD and slows memory loss by sending irisin to the brain.
Irisin is sent from muscles to various tissues throughout the body during exercise. It was initially found to promote fat metabolism, turning white fat cells into brown ones, which burn more energy. It was only later recognized that it also plays a role in the brain.
More than muscle
This new study makes a pretty compelling case that exercise, working through irisin, can protect memories from the neurodegeneration that wreaks such havoc on the minds and lives of Alzheimer’s patients. The researchers first showed that irisin levels are lower in the brains of people and mice with AD than in age-matched healthy controls, a correlation that indicated a closer look was called for.