Research has shown that even a moderate amount of exercise every day can slow the progression of Alzheimer’s disease in older people at risk.
People are often recommended to walk 10,000 steps a day as part of a healthy routine, but scientists have found that taking more than 3,000 steps has been shown to delay the brain changes and cognitive decline experienced by Alzheimer’s patients.
A 14-year study found that people who walked 3,000 to 5,000 steps a day delayed cognitive decline by an average of 3 years, and those who walked 5,000 to 7,000 steps a day delayed cognitive decline by 7 years.
“We encourage older adults at risk for Alzheimer’s disease to consider making small changes to their activity levels and building lasting habits that protect or benefit brain and cognitive health,” said the study’s first author, Dr. Wai-Ying Yau of Mass General Brigham Hospital in Boston.
Dementia affects approximately 50 million people worldwide, with Alzheimer’s disease being the most common cause. More than half a million people in the UK have Alzheimer’s disease. This condition is associated with the buildup of two toxic protein forms in the brain: amyloid-beta plaques and tau tangles.
Yau and her colleagues analyzed data from 296 people between the ages of 50 and 90 who had no cognitive impairment at the start of the study. Data included annual cognitive assessments, step counts measured with a pedometer, and PET imaging to detect amyloid and tau levels in the volunteers’ brains.
People who initially had less brain amyloid showed little cognitive decline or tau protein buildup over the course of the study. The risk of developing Alzheimer’s was essentially higher in people with higher baseline amyloid levels, and among them, more steps were associated with slower rates of cognitive decline and delayed tau protein accumulation. In sedentary people, tau accumulation and cognitive decline were much faster. Reported in the journal Nature Medicine.
Although scientists cannot rule out reverse causality, where early brain changes in Alzheimer’s disease lead to less walking in later life, the data suggest that physical activity is protective. “Although randomized clinical trials are needed to prove cause and effect, it is very encouraging that physical activity can help correct someone’s trajectory,” Yau said. “If you have amyloid, being more physically active may slow the decline.”
It’s unclear how exercise may help, but physical activity can all play an important role in improving blood flow, reducing inflammation, and increasing levels of certain hormones and growth factors. “In terms of potential mechanisms, this is a million-dollar question that we would like to look at in future research,” Yau said.
Dr Julia Dudley, from Alzheimer’s Research UK, said: “These findings suggest that even moderate walking of around 5,000 steps per day is associated with slowing the build-up of tau protein in the brain, one of the main causes of Alzheimer’s disease. This provides a clearer picture of how everyday activity can support brain health and influence the root causes of Alzheimer’s disease.”
“More research, including clinical trials, is needed to determine the direct impact of physical activity on preventing and slowing the progression of dementia and underlying disease causes. But studies like this reinforce that simple changes in lifestyle can help keep our brains healthy for longer.”
