In research published in the journal “Nature Medicine,” researchers from Massachusetts General Hospital Brigham reported that physical activity is associated with lower rates of cognitive decline in older adults with high levels of “beta-amyloid” protein, which is directly linked to Alzheimer’s disease.
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.
In contrast, faster accumulation of tau proteins in the brain was observed in people who did not exercise, in addition to faster deterioration in cognition and daily performance.
Lead researcher in the Department of Neurology at Massachusetts General Hospital Brigham, Dr. Jasmeer Chhatwal, said:
* “This sheds light on why some people who appear to be on the Alzheimer’s disease path do not deteriorate as quickly as others.”
* “Lifestyle factors appear to affect the early stages of Alzheimer’s disease, suggesting that lifestyle changes may slow the onset of cognitive symptoms if we act early.”
The researchers analyzed data from 296 participants between the ages of 50 and 90 in the Harvard Aging Brain Study, all of whom had good cognitive health at the start of the study. They used positron emission tomography (PET) scans of the brain to measure baseline levels of amyloid beta in plaques and tau in tangles, and assessed participants’ physical activity using pedometers attached to the waist belt.
The results showed that an increase in the number of steps was associated with slower rates of cognitive decline and slower accumulation of tau proteins in participants with high baseline levels of amyloid beta. Statistical modeling by the researchers indicated that most of the benefits of physical activity associated with slower cognitive decline were due to slowing the accumulation of tau protein.
In contrast, in people with low baseline levels of beta amyloid, there was very little cognitive decline or accumulation of tau proteins over time, and there were no significant associations with physical activity.
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