Increasing your steps by even a little bit may help slow down the progression of Alzheimer\u2019s disease among people at heightened risk, according to a new study.<\/p>\n
In a paper published in\u00a0Nature Medicine<\/a>, Mass General Brigham researchers\u00a0found that physical activity was associated with slower rates of cognitive decline in older adults with elevated levels of amyloid-beta, a protein associated with Alzheimer\u2019s.<\/p>\n Cognitive decline was delayed by three years on average for people who walked just 3,000-5,000 steps per day, and by seven years in people who walked 5,000-7,500 steps per day. Sedentary individuals had a significantly faster buildup of tau proteins in the brain and more rapid declines in cognition and daily functioning.<\/p>\n \u201cThis sheds light on why some people who appear to be on an Alzheimer\u2019s disease trajectory don\u2019t decline as quickly as others,\u201d said senior author\u00a0Jasmeer Chhatwal<\/a> of the Mass General Brigham\u00a0Department of Neurology. \u201cLifestyle factors appear to impact the earliest stages of Alzheimer\u2019s disease, suggesting that lifestyle changes may slow the emergence of cognitive symptoms if we act early.\u201d<\/p>\n \u201cLifestyle changes may slow the emergence of cognitive symptoms if we act early.\u201d<\/p>\n<\/blockquote>\n The researchers analyzed data from 296 participants aged 50-90 years old in the\u00a0Harvard Aging Brain Study<\/a>\u00a0who were all cognitively unimpaired at the beginning of the study. They used PET brain scans to measure baseline levels of amyloid-beta in plaques and tau in tangles and assessed the participants\u2019 physical activity using waistband pedometers. The participants received annual follow-up cognitive assessments for between two and 14 years (average, 9.3 years), and a subset received repeated PET scans to track changes in tau.<\/p>\n Higher step counts were linked to slower rates of cognitive decline and a slower buildup of tau proteins in participants with elevated baseline levels of amyloid-beta. The researchers\u2019 statistical modeling suggested that most of the physical activity benefits associated with slowing cognitive decline were driven by slower tau buildup. By contrast, in people with low baseline levels of amyloid-beta, there was very little cognitive decline or accumulation of tau proteins over time and no significant associations with physical activity.<\/p>\n \n3 years<\/p>\n Of delayed cognitive decline on average for those who walk 3,000-5,000 steps daily (7 years for those who get 5,000-7,500 steps)\n<\/p>\n \u201cWe are thrilled that data from the Harvard Aging Brain Study has helped the field better understand the importance of physical activity for maintaining brain health,\u201d said co-author\u00a0Reisa Sperling<\/a>, a neurologist in the Mass General Brigham Department of Neurology and co-principal investigator of the Harvard Aging Brain Study. \u201cThese findings show us that it\u2019s possible to build cognitive resilience and resistance to tau pathology in the setting of preclinical Alzheimer\u2019s disease. This is particularly encouraging for our quest to ultimately prevent Alzheimer\u2019s disease dementia, as well as to decrease dementia due to multiple contributing factors.\u201d<\/p>\n Looking ahead, the researchers plan to dive deeper into which aspects of physical activity may be most important, for example exercise intensity and longitudinal activity patterns. They also plan to investigate the biological mechanisms linking physical activity, tau buildup, and cognitive health. Critically, the authors believe that this work may help design future clinical trials that test exercise interventions to slow late-life cognitive decline, especially in individuals who are at heightened risk due to preclinical Alzheimer\u2019s disease.<\/p>\n\n