The health benefits of an afternoon nap have been long extolled, but a new need for excessive daytime napping may come with a red flag. Researchers from UC San Francisco say the trait could be an early warning sign of Alzheimer's, reports Live Science. In the new study in Alzheimer's & Dementia, researchers found that the disease directly attacks parts of the brain responsible for keeping us awake. Scientists aren't trying to alarm those who enjoy a regular snooze, but adults who develop a new pattern of daytime napping—particularly when their nighttime sleep doesn't change—might want to pay heed. "It only gets worrisome when it represents a change," researchers Lea Grinberg tells USA Today. "For instance, in some cultures, it is pretty common to nap every day. This is quite OK."
The study suggests that a shift to excessive daytime napping might be one of the earliest warnings signs of the disease. Researchers studied the brains of 13 Alzheimer's patients who died and compared them to the brains of seven people who did not have the disease. The Alzheimer's patients had buildups of telltale tau proteins in the brain regions that work as a network to help us sleep. "It's remarkable because it's not just a single brain nucleus that's degenerating, but the whole wakefulness-promoting network," says lead author Jun Oh of UCSF in a news release. "This means that the brain has no way to compensate, because all of these functionally related cell types are being destroyed at the same time." (Read more Alzheimer's Disease stories.)