Walking 3,000 Steps Daily Could Help Slow Alzheimer’s Disease Decline

Older adults, particularly those at greater risk for Alzheimer’s disease, might slow cognitive decline by walking just 3,000 steps daily. The underlying reasons for this effect remain unclear; however, it could be linked to how regular exercise influences inflammation and blood circulation in the brain.

Earlier studies connecting regular physical activity to reduced cognitive decline often depended on individuals recalling their activity levels, with limited exploration into why staying active might offer such benefits.

To overcome these constraints, Wai Ying Wendy Yau and colleagues at Harvard University objectively tracked the physical activity of 296 cognitively healthy adults aged 50 to 90 through step-counting devices over a week.

Most participants also underwent brain imaging to assess baseline levels of misfolded proteins known as tau and beta-amyloid, which are believed to contribute to Alzheimer’s disease. These levels were typically evaluated every 2 to 3 years over a follow-up duration spanning 3 to 14 years. Participants took annual cognitive tests measuring memory and processing speed.

The research team estimated exercise’s impact on cognitive decline by feeding data from step counts, brain imaging, and cognitive evaluations into a statistical model. They discovered that participants with elevated levels of misfolded beta-amyloid who walked between 3,000 to 5,000 steps daily considerably slowed tau accumulation, but not beta-amyloid.

“[Exercise is] somehow hindering the spread of tau protein, which is more closely linked to symptom onset in individuals with [Alzheimer’s disease] than amyloid beta,” remarked Charles Marshall at Queen Mary University of London.

This was associated with an approximate 40 percent reduction in cognitive decline over a nine-year average follow-up, compared to participants taking fewer than 3,000 steps daily, categorized as inactive. Researchers, however, did not have data on whether any participants were diagnosed with Alzheimer’s during the follow-up.

Conversely, walking between 5,000 and 7,500 steps daily further slowed tau buildup, leading to a 54 percent reduction in cognitive decline compared to inactivity. However, exceeding 7,500 steps daily did not result in additional cognitive improvements. “The benefits with tau and cognition eventually reach a plateau,” Yau noted.

While the exact mechanisms through which regular exercise yields these effects remain uninvestigated, potential causes may include: Physical activity that diminishes inflammation purportedly caused by beta-amyloid and tau misfolding, disrupting neural connections, and damaging cells. Moreover, exercise could enhance blood flow or boost levels of protective hormones in the brain.

Nonetheless, this study does not conclusively establish that walking 5,000 steps daily directly contributes to slowing cognitive decline. Unidentified or unnoticed pre-existing conditions might impact individuals’ capacity and enthusiasm for exercising, according to Marshall. Various lifestyle and socio-economic factors that the research team considered may also affect activity levels and tau counts.

Nevertheless, given that regular exercise offers numerous health advantages, is inexpensive, and generally has few side effects, individuals should be encouraged to aim for at least 3,000 steps daily, even if the exact impact on cognitive function remains uncertain. “I always advise people not to obsess over numeric goals for step counts. It’s merely a target,” said Marshall. “What truly matters is maintaining regular physical activity, which doesn’t have to be at large volumes or high intensity.”

Prior research suggests that consistent lifestyle alterations, including exercise, can reverse cognitive decline. However, Yau emphasizes the necessity for further studies that randomly assign participants to distinct daily step counts to differentiate the effects of exercise from other lifestyle modifications and determine whether it genuinely slows tau accumulation.