For several years, fitness experts have been telling us to walk 10,000 steps a day to help reduce the risks of obesity, heart disease, diabetes, high blood pressure, and depression. A new comprehensive study, published in the September 2022 edition of JAMA Neurology (from the Journal of the American Medical Association), appears to correlate a lower risk of all forms of dementia with walking 10,000 steps (about five miles) a day.
Details of the Dementia Study
Four doctors oversaw a comprehensive study in Great Britain that examined the medical data of more than 78,000 adult participants from 2015 to 2022. They were ages 40 to 79, with an average age of 61.1. All of them were outfitted with accelerometers that collected data over seven years. A total of 866 participants developed some form of dementia throughout the study period.
The researchers found that walking 3,800 steps a day reduced the risk of all forms of dementia by 25 percent. Walking 9,826 steps a day lowered the risk of dementia by 50 percent. The ideal cadence was 112 steps per minute, nearly one step every half a second, as a brisk walk for 30 minutes at the peak of exercise. Researchers noted that purposeful steps, or 40 steps or more per minute, were the key to this benefit, not just walking normally from one room to another.
Researchers also said that the relationship is nonlinear, meaning doubling the steps per day doesn't lower the risk by half. However, researchers did take into account the lifestyles, medical histories, and nutritional consumption of the participants when factoring in all known risk factors for dementia.
The takeaway is that the more people walk, the lower their risks of all forms of dementia when everything else is taken into account. What sets this study apart from others is the large sample size (nearly 80,000 adults) and the fact that every participant was outfitted with monitored accelerometers that measured their daily steps.
Why Is This New Study Important?
This study seems to point to a way to combat dementia even if other risk factors are present. It doesn't say someone won't face cognitive decline in their elder years because a dementia diagnosis can take years to develop. But this is the first solid evidence, using hard data from tens of thousands of participants, that shows physical activity represents one way to ward off dementia later in life.
While the study only focused on walking, which is relatively easy to do, it didn't take into account other brisk forms of exercise such as riding bicycles, swimming, rowing, and strength training, all of which can make people work up a sweat and increase their heart rate for an extended period.
Finding ways to battle age-related cognitive decline is important because humans are living longer. The prevalence of dementia is expected to rise to 150 million cases by 2050 due to an aging population that will live longer than previous generations. The costs of dementia are also high. In 2017, a study from the Journal of the American Geriatric Society said that the average cost of treating one person with dementia from the time of diagnosis was $321,780, with families shouldering the burden of 70 percent of those costs in the United States.
Another positive side to the fight against dementia comes from a study by RAND Corporation that notes the prevalence of dementia in people 65 and older declined by 3.7 percent from 2000 to 2016. Researchers noted that they don't know why dementia declines over 16 years, but they believe rising levels of education, reduction in smoking, and better treatment of key cardiovascular risk factors such as high blood pressure have led to fewer dementia cases.
Dementia comes from abnormal changes in the brain. It affects 55 million people worldwide, with around 70 percent of cases coming from Alzheimer's disease, according to the World Health Organization. Around 6.2 million Americans have some form of dementia.
Risk factors for dementia include age, depression, alcohol consumption, vitamin deficiencies, problems with the thyroid, side effects of certain medications, and hearing loss. However, there is no singular cause of dementia, much like there is no single cause of metabolic disorders (such as diabetes) or heart disease.
What Do Other Dementia Studies Say About Physical Activity?
A study in 2021 in Korea stated that people who were more active seemed to show fewer incidences of dementia, though that research was limited by people self-reporting their activity levels. The report examined survey data over four years and more than 62,000 people ages 65 or older.
A British study in 2021 analyzed 9,275 people aged 50 and older over the course of 15 years. It noted that even small amounts of physical activity can reduce the risk of dementia-related disorders, and nearly three-fourths (69 percent) of study participants were classified as moderately active to highly active.
A 2019 population-based study examined the medical records of 800 women from 1968 to 2012, aged 38 to 54. It found that physical activity in midlife (40 to 50 years old) was associated with a reduced risk of dementia later in life.
Combatting dementia at these ages is important, considering the average age of the onset of dementia is 83.7 years old, and it's most common in people over 65. Engaging in physical activity at a younger age may be a key to warding off dementia 30 to 40 years later.
What Are the Best Ways to Prevent Dementia?
Of the risk factors for dementia, age, genetics, race, and gender are the ones people cannot control. Lifestyle factors may prevent dementia, and medical studies highly recommend taking preventive measures decades before the onset of dementia.
Improving blood pressure through diet or medication can prevent vascular problems in the brain. People should eliminate smoking and drinking because their effects are cumulative and they damage brain cells. Eating a balanced diet, particularly one rich in nutrients, can prevent inflammation and oxidative stress, both of which can exacerbate dementia later in life. Depression is a risk factor for dementia, so it's vital to maintain emotional health. Sleep helps regulate and heal the body at night, so the right amount of sleep is essential.
Improving hearing loss can lessen the strain on the brain by keeping it more engaged and active, with higher neurological activity due to socialization.
Head injuries can also cause dementia, so people should avoid things like regular blows to the head and also wear a helmet when riding a bike or motorcycle.
Nearly one in three cases of dementia is preventable. The overall key to preventing dementia is blood flow to the brain, notes Johns Hopkins University. Narrowed blood vessels in the brain can restrict the flow of nutrients and oxygen, which, over time, can cause gradual cognitive decline. Taking care of the body should start decades before people reach their 70s and 80s, sometimes as early as their 30s and 40s.
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