Researchers at Dalhousie University have found that frailty, more so than amyloid plaques and tangles in the brain, is a key risk factor for developing Alzheimer’s disease and other forms of dementia.
PhD candidate Lindsay Wallace, lead author, and her supervisor Dr. Kenneth Rockwood, are optimistic their findings will be influential, as they were published this week in Lancet Neurology — one of the highest-impact journals in the field.
This study is the first to examine amyloid plaques and tangles in post-mortem brain tissues, in relation to both the subjects’ frailty index and the severity of their dementia symptoms when they were alive. The frailty index is a score of relative frailty based on the accumulation of deficits in physical health and ability to function.
New research combining postmortem examination of brain tissue with testing during life has revealed what researchers believe to be an as-yet unexplained connection: higher levels of physical activity (PA) and motor skills seem to create a “cognitive reserve” that buoys cognitive performance during life, even in the presence of Alzheimer’s disease (AD), Lewy body disease, and other brain pathologies associated with dementia.
For the study, published ahead of print in Neurology, researchers examined brain tissue from 454 participants involved in the Rush Memory and Aging Project (MAP). The subjects participated in a battery of annual clinical assessments and agreed to brain donation at the time of death. The clinical tests included 21 cognitive assessments, an analysis of 10 motor abilities, and an estimation of total daily PA drawn from accelerometers worn constantly for 10 days (researchers in this study used only the first 7 days’ data).
Exercise is just as good for the brain as it is for the body, a growing body of research is showing. And one kind in particular—aerobic exercise—appears to be king.
“Back in the day, the majority of exercise studies focused on the parts of the body from the neck down, like the heart and lungs,” says Ozioma Okonkwo, assistant professor of medicine at the University of Wisconsin School of Medicine and Public Health. “But now we are finding that we need to go north, to the brain, to show the true benefits of a physically active lifestyle on an individual.”
Exercise might be a simple way for people to cut down their risk for memory loss and Alzheimer’s disease, even for those who are genetically at risk for the disease. In a June study published in the Journal of Alzheimer’s Disease, Okonkwo followed 93 adults who had at least one parent with Alzheimer’s disease, at least one gene linked to Alzheimer’s, or both. People in the study who spent at least 68 minutes a day doing moderate physical activity had better glucose metabolism—which signals a healthy brain—compared to people who did less.
Scientists have more evidence that exercise improves brain health and could be a lifesaving ingredient that prevents Alzheimer’s disease.
In particular, a new study from UT Southwestern’s O’Donnell Brain Institute suggests that the lower the fitness level, the faster the deterioration of vital nerve fibers in the brain. This deterioration results in cognitive decline, including memory issues characteristic of dementia patients.
“This research supports the hypothesis that improving people’s fitness may improve their brain health and slow down the aging process,” said Dr. Kan Ding, a neurologist from the Peter O’Donnell Jr. Brain Institute who authored the study.