LONDON – A growing body of research suggests that physical activity not only improves executive function and cerebral blood flow but may also reduce amyloid and tau levels in the brain.
The new findings were presented here at Alzheimer’s Association International Conference (AAIC) 2017.
Much of the focus of this year’s AAIC meeting was on lifestyle interventions – healthy eating, reduced stress, adequate sleep, and increased physical activity – to help prevent dementia. Some experts believe that of all lifestyle factors, exercise is tops when it comes to preserving cognition.
In recent years, the identification of biomarkers for Alzheimer’s disease (AD) has made it possible to compare levels of amyloid-beta (Aβ) and tau ― both hallmarks of AD ― in those who are and those who are not physically active.
One new study presented here, led by Belinda M. Brown, PhD, School of Psychology and Exercise Science, Murdoch University, Perth, Australia, evaluated the relationship between exercise levels and brain amyloid load in carriers of genetic mutations that cause autosomal-dominant AD.
The analysis included data from the Dominantly Inherited Alzheimer Network for 139 presymptomatic mutation carriers. These patients are destined to develop AD and know approximately when they will start having symptoms.
From self-reports of exercise, the researchers categorized patients into those reporting fewer than 150 minutes per week of (low exercise) and those reporting 150 minutes or more per week (high exercise).
The researchers also had information on brain amyloid load, as quantified by Pittsburgh compound B positron-emission tomography (PiB PET). They stratified patients in order to investigate those with high brain amyloid levels (PiB+).
Compared to the high-exercise group, the low-exercise group was older (38.6 years vs 33.7 years) and had more depressive symptoms, as measured by the Geriatric Depression Scale (2.2 vs 1.4).
When the entire cohort of mutation carriers was examined, there were no differences in amyloid load between patients in the low-exercise group and those in the high-exercise group. However, for the 16 patients with PiB+ in the low-exercise group, the mean level of brain amyloid was higher than in the 55 patients with PiB+ who were in the high-exercise group (P = .007).
Slower Accumulation of Amyloid
The researchers were able to show that Aβ in those in the high-exercise group accumulated at a slower rate relative to what would be expected.
“In mutation carriers of Alzheimer’s disease, researchers can estimate how many years away an individual is from developing Alzheimer’s symptoms, based on their age and the average age of onset of others with the same mutation,” Dr Brown told Medscape Medical News.
“The results suggest that higher levels of exercise may delay the accumulation of Alzheimer’s pathology and subsequent symptom onset in Alzheimer’s disease mutation carriers..