A new study reveals that physical activity was associated with slower rates of cognitive decline in older people with high levels of beta-amyloid, a protein linked to Alzheimer’s disease.
The researchers found that older people who walked less than 3,000 steps per day, and who had high levels of beta-amyloid protein in the brain, showed faster cognitive decline and greater accumulation of tau proteins in the brain compared to more active individuals.
The study suggests that increasing the number of steps, even slightly, may help slow the progression of Alzheimer’s disease in people at highest risk.
The study was conducted by researchers from Massachusetts Brigham General Hospital in the United States, and the results were published in the journal Nature Medicine on November 3, and the Eurek Alert website wrote about it.
Cognitive decline was delayed by an average of 3 years in people who walked between 3,000 and 5,000 steps per day, and by 7 years in people who walked between 5,000 and 7,500 steps per day.
Individuals who were not physically active had a much faster accumulation of tau proteins in the brain, and a faster decline in cognition and daily performance. Tau protein is a neuronal protein that is necessary for the proper functioning of nerve cells, but it forms aggregates in Alzheimer’s disease.
“This sheds light on why some people who appear to be on the path to Alzheimer’s disease do not deteriorate as quickly as others,” said lead researcher Jasmir Chhatwal, MD, of the Department of Neurology at Massachusetts General Brigham Hospital.
He added: “Lifestyle factors appear to influence the early stages of Alzheimer’s disease, suggesting that lifestyle changes may slow the onset of cognitive symptoms if we act early.”
Protect the brain through physical activity
The researchers analyzed data from 296 participants between the ages of 50 and 90 in the Harvard Brain Aging Study, who had no cognitive impairment at the start of the study.
The researchers used positron emission tomography scans of the brain to measure baseline levels of amyloid beta and tau protein, and assessed the participants’ physical activity using waist-belt-mounted pedometers.
Higher step counts were associated with slower rates of cognitive decline and slower accumulation of tau proteins in participants with high baseline levels of amyloid beta.
The results indicated that most of the benefits of physical activity associated with slowing cognitive decline were driven by slower accumulation of tau.
In people with lower baseline levels of amyloid beta, there was very little cognitive decline or buildup of tau proteins over time and there was no significant association with physical activity.
“We want to empower people to protect their brains and cognitive health by staying physically active,” said Dr. Wei Ying Wendy Yao, a cognitive neurologist in the Department of Neurology at Massachusetts General Hospital. “Every step counts, and even small increases in daily activities can add up over time to lead to sustainable changes in habits and health.”