Moving around for just five minutes a day lowers dementia risk, according to a new study

Most people hear “150 minutes a week” and stop before they start. New evidence says just a few minutes each can still lower the risk of developing dementia, and that message lands with unusual clarity.

A large analysis linked as little as 35 minutes a week of movement with a sharply lower chance of dementia over about four years, and the reductions grew with more activity.

The peer reviewed study followed people wearing wrist trackers, so it reflected actual movement rather than memory of it.

Dementia risk and movement

Study lead Amal Wanigatunga, PhD, MPH, at the Johns Hopkins Bloomberg School of Public Health, examined how moderate to vigorous physical activity relates to first time dementia diagnoses.

The dose-response relationship (the pattern showing how different levels of exposure to something affect the outcome) looked clear, with the steepest drop for people who previously did none.

Compared with zero activity, about 35 to 69.9 minutes a week tied to roughly 60 percent lower risk, 70 to 139.9 minutes tied to roughly 63 percent lower risk, and 140 minutes or more tied to roughly 69 percent lower risk.

Each 30 minute bump in weekly activity linked to about a 4 percent lower risk, expressed as a hazard ratio that quantifies relative risk in time-to-event analysis (a method that measures how long it takes for a specific event, like disease onset, to occur).

Those numbers came from devices rather than diaries, which reduces recall errors that often blunt signals in lifestyle research. They also line up with a simple idea that small steps away from zero may deliver the biggest early gains.

Studying dementia risk

The team analyzed nearly 90,000 adults from the UK Biobank who wore a wrist accelerometer (a device that measures motion or acceleration, often used in fitness trackers) for one week between 2013 and 2015.

These motion sensors quantify intensity and duration, which allowed the researchers to estimate weekly time spent moving at moderate or vigorous levels.

Participants were then followed for a mean of 4.4 years, during which first time dementia diagnoses were recorded from linked health records.

Statistical models adjusted for age, sex, and medical conditions, then estimated risk using the hazard ratio approach common in cohort studies.

The analysis also classified people by frailty, a clinical pattern of lower reserve and higher vulnerability tied to slower walking speed, weakness, and weight loss.

That let the team test whether age related vulnerability erased the apparent benefit of moving more.

Frail does not mean futile

The association between more movement and less dementia looked similar across frailty status, which matters because many older adults find high targets discouraging.

The pattern suggests a low starting dose can still be worthwhile in people who need cautious, stepwise goals.

“Our findings suggest that increasing physical activity, even as little as five minutes per day, can reduce dementia risk in older adults,” said Wanigatunga.

The broader point is pragmatic, start somewhere that fits the person, then build.

How this fits with guidelines

Federal guidance says adults should aim for at least 150 to 300 minutes a week of moderate activity, or 75 to 150 minutes of vigorous activity, plus muscle strengthening on two days. 

This new work does not replace those targets, it shows benefits may begin well below them. For many readers, that means doing what is doable now and letting consistency grow volume over time.

Why movement lowers dementia risk

Exercise affects blood vessels, inflammation, insulin sensitivity, and brain growth factors that support neurons.

In a randomized trial, a year of moderate aerobic training increased hippocampal volume by about 2 percent and improved memory in older adults.

That same study found higher circulating brain derived neurotrophic factor (BDNF) – a protein that supports the growth and survival of nerve cells – after training.

BDNF is a molecule linked to synaptic plasticity and learning. While structure and chemistry differ from disease endpoints, the direction of change points to plausible biological support for the observational pattern.

Dementia remains common and costly, which raises the stakes for realistic prevention strategies. In 2025, an estimated 7.2 million Americans age 65 and older are living with Alzheimer’s disease.

Risk rises with age, and many people will live long enough to face some degree of cognitive decline. That context makes accessible, low barrier actions attractive, especially when other risk factors like blood pressure and blood sugar are also addressed.

A low barrier starting point

This was not a randomized trial, so it cannot prove that exercise itself prevents dementia.

The researchers ran sensitivity checks to reduce the chance that very early, undiagnosed decline lowered activity, and the associations held after removing early cases.

It is also important to remember that movement sits alongside other levers like sleep, hearing care, and cardiovascular health.

Still, the signal here aligns with many other cohorts and offers a straightforward on-ramp for people who feel boxed out by lofty goals.

Dementia risk and human health

Intensity matters, but it does not need to be all out. Moderate effort includes brisk walking that raises heart rate and breathing a bit, while vigorous effort is hard enough to make talking difficult for short stretches.

Minutes add up across a week, which means small bouts can count the same as longer sessions if the intensity is there. For someone easing in, a short daily slot can open the door to more minutes and more confidence.

Very small amounts of movement were linked to meaningfully lower dementia risk, and the curve favored people moving away from zero.

The pattern looked similar in people living with frailty, which helps counter the idea that benefit requires high volume or intensity.

The smartest path uses a laddered approach that respects medical limits and builds habits. It is a message for families as much as individuals, because support makes behavior change more likely to stick.

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