Maintaining a Healthy Sleep Cycle Can Prevent Alzheimer's Disease, New Research Says

Alzheimer's disease is a form of dementia that leads to memory loss and cognitive decline. The disease plagues millions of people across the globe, which is why research into preventative measures is at the forefront of many scientists' minds. In fact, a recent study conducted by researchers from the Rensselaer Polytechnic Institute found a new way to prevent the aggressive disease: better sleep habits.

The researchers say a person's circadian rhythm plays an important role in eliminating a protein that clumps up in the brain and leads to dementia. They found that healthy sleep habits and avoiding interruptions while sleeping increases the immune system's ability to flush out the protein Amyloid-Beta 42 (AB42), as well as other harmful proteins. "Circadian regulation of immune cells plays a role in the intricate relationship between the circadian clock and Alzheimer's disease," says Jennifer Hurley, an expert in circadian rhythms, in a university release. "This tells us a healthy sleep pattern might be important to alleviate some of the symptoms in Alzheimer's disease, and this beneficial effect might be imparted by an immune cell type called macrophages/microglia."

Maintaining a healthy sleep rhythm is so important because the circadian cycle prepares the body for times it should be awake and when it should be asleep. Disrupting these rhythms can increase the risk of mental and physical illness, including diabetes, cancer, and dementia. In experiments to test the connection between the circadian cycle and eliminating dementia-causing proteins, study authors found that the amount of AB42 that healthy macrophages can ingest changes with a patient's sleep pattern. No such connection was found in immune cells that did not have an internal clock to regulate them.

While there are a handful of ways scientists say you can decrease your risk of dementia—think creating healthy sleep habits and eating antioxidant rich foods—there aren't many ways to predict or diagnose dementia early on. Another new study, however, suggests the retina could be used to do so in the future. Researchers from the University of Otago in New Zealand believe the thinning of a person's retina (the tissue that lines the back of the eye) in middle age is linked to cognitive performance in early and adult life.

To obtain their findings, researchers looked at data from the Dunedin Study, a long-running study that followed the lives of over 1,000 babies born in the early 1970s. Fifty years later, researchers analyzed a subgroup of 865 adults who had eye scans at 45-years-old, along with a handful of neuropsychology tests in adulthood and early childhood. The thickness of two different areas of the retina were measured on the eye scans. According to the analysis, participants with thinner retinal layers scored lower on cognitive tests, both as adults and when they were examined as children.

While much more research on the connection between a thin retina and Alzheimer's disease is needed, the team behind these findings believes their research might one day lead toward an eye test that could help predict a person's risk for diseases that negatively impact cognitive function. "The findings suggest that [retinal thickness] could be an indicator of overall brain health," says Barrett-Young, who led the study.