A new study reveals that even modest physical activity can significantly slow Alzheimer’s disease progression in at-risk older adults. Walking 3,000-5,000 steps daily delayed cognitive decline by three years, while 5,000-7,500 steps offered a seven-year delay. This benefit is linked to reduced tau protein accumulation in the brain. “Lifestyle factors appear to impact the earliest stages of Alzheimer’s disease, suggesting that lifestyle changes may slow the emergence of cognitive symptoms if we act early,” the researchers said.

Alzheimer’s disease affects millions of people globally. It is one of the leading causes of death, disability and dependency among older people. Over seven million Americans are living with Alzheimer’s disease (AD), according to the Alzheimer’s Association. This number is projected to rise to nearly 13 million by 2050. Globally, about57 million people had dementia in 2021, as per the World Health Organization. A new study led by Mass General Brigham researchers found that even a modest amount of physical activity can significantly slow down AD in at-risk older adults. The findings are published in Nature Medicine.**

How 5,000 steps can make a difference

**The researchers found that even a slight increase in physical activity can significantly slow the progression of Alzheimer’s disease among people at heightened risk. The study showed that physical activity was associated with slower rates of cognitive decline in older adults with elevated levels of amyloid-beta, a protein linked to Alzheimer’s.In people who walked just 3,000–5,000 steps per day, cognitive decline was delayed by three years, while those who walked 5,000–7,500 steps per day saw a delay of seven years. On the other hand, those with a sedentary lifestyle experienced faster build-up of tau proteins in the brain and more rapid declines in cognition and daily functioning.“This sheds light on why some people who appear to be on an Alzheimer’s disease trajectory don’t decline as quickly as others. Lifestyle factors appear to impact the earliest stages of Alzheimer’s disease, suggesting that lifestyle changes may slow the emergence of cognitive symptoms if we act early,” said senior author Jasmeer Chhatwal, MD, PhD, of the Mass General Brigham Department of Neurology, in a statement.

Researchers observe DNA methylation in Alzheimer’s disease

Impact of physical activity on the brain

To understand the impact of exercise on Alzheimer’s disease, the researchers analysed data from the Harvard Aging Brain Study, which involved 296 participants aged 50–90 years, all cognitively unimpaired at the beginning of the study. Using PET brain scans, the researchers measured baseline levels of amyloid-beta in plaques and tau in tangles and assessed participants’ physical activity using waistband pedometers. Participants underwent yearly cognitive tests for two to 14 years (an average of 9.3 years), and some had follow-up PET scans to monitor changes in tau levels.They found that higher step counts were linked to slower rates of cognitive decline and a slower build-up of tau proteins in participants with elevated baseline levels of amyloid-beta. The researchers noted that the cognitive benefits of physical activity were largely due to a slower accumulation of tau in the brain. In contrast, people with low baseline levels of amyloid-beta showed very little cognitive decline or accumulation of tau proteins over time and no significant associations with physical activity.“We are thrilled that data from the Harvard Aging Brain Study have helped the field better understand the importance of physical activity for maintaining brain health. These findings show us that it’s possible to build cognitive resilience and resistance to tau pathology in the setting of preclinical Alzheimer’s disease. This is particularly encouraging for our quest to ultimately prevent Alzheimer’s disease dementia, as well as to decrease dementia due to multiple contributing factors,” said co-author Reisa Sperling, MD, a neurologist in the Mass General Brigham Department of Neurology and co-principal investigator of the Harvard Aging Brain Study.Emphasising the importance of physical activity to improve cognitive health, first author Wai-Ying Wendy Yau, MD, a cognitive neurologist in the Mass General Brigham Department of Neurology, said, “We want to empower people to protect their brain and cognitive health by keeping physically active. Every step counts — and even small increases in daily activities can build over time to create sustained changes in habit and health.”Note: The information provided in this article is for educational purposes only and is not intended as medical advice. Always consult a qualified healthcare professional before starting any new medication or treatment and before changing your diet or supplement regimen.