Physical Activity Helps Prevent Mental Decline

Walking reduces the risk of dementia and boosts mental function, according to two studies reported in the Journal of the American Medical Association.

In one study, Dr. Robert D. Abbott, a professor of biostatistics at the University of Virginia School of Medicine, and his team evaluated more than 2,000 men aged 71 to 93 who were part of the Honolulu-Asia Aging Study.

The researchers asked the men about their typical daily walking and then tested them for dementia.

Other studies have found physical activity may reduce the risk of dementia, Dr. Abbott says, but whether the association holds true for low-intensity activities such as walking has not been known.

Dementia describes a group of symptoms related to brain function changes, such as memory problems and behavior changes. November is National Alzheimer's Disease Month.

Walking Lowers Dementia Risk

"Those who walked less than a quarter mile a day were nearly twice as likely to develop dementia as those who walked more than two miles a day," Dr. Abbott says.

"These were all retired men," he notes. And the walking was not necessarily done in a formal setting such as a gym. He adds: "They could be walking to the grocery, or walking for another errand."

The distance walked by the men was assessed from 1991 to 1993. Exams to test their neurological functioning were done from 1994 to 1996 and again from 1997 to 1999.

In the second study, Dr. Jennifer Weuve, a research fellow at the Harvard School of Public Health, and her colleagues surveyed more than 18,000 women, aged 70 to 81, who were part of the long-running Nurses' Health Study.

In telephone interviews conducted from 1995 to 2001, the women were tested for verbal memory, attention, and other gauges of cognitive functioning. They were asked about their typical physical activity, and the researchers converted that activity into what it was in terms of miles walked.

"The more active women had better cognition," Dr. Weuve said.

Among women who put in the highest of five levels of activity - the equivalent of six or more hours of weekly walking at an easy pace - there was a 20 percent lower risk of cognitive impairment compared to women in the lowest level of activity - the equivalent of walking less than two hours a week at an easy pace.

At two hours of walking a week, the health benefits first became apparent.

"Memory, attention and learning ability may be preserved by walking two to three hours a week at an easy pace," says Dr. Weuve, defining an easy pace as taking about 20 or 30 minutes to cover a mile.

For those who walk at a pace of 16 to 20 minutes per mile, about one and a half hours a week would do it, she notes.

Ideally, she says, walking six hours a week at an easy pace - or expending the same amount of energy at another exercise - is associated with the most benefits.

Exercise Benefits Heart, Too

Physical activity benefits the cardiovascular system, Dr. Weuve comments, and "there is some evidence that better cardiovascular health is related to better cognitive function.

"Physical activity also appears to have a direct effect on the brain itself," she says. "It appears to promote the production of chemicals in the brain, called nerve growth factors, that improve the brain cells' survival and growth."

Dr. Abbott agrees: "Those who are more physically active tend to have a better cardiovascular risk profile," he says. "And maybe that helps protect against dementia."

The findings come as no surprise to Dr. Gary Small, director of the UCLA Center on Aging, who found in one of his recent studies that lifestyle changes such as regular exercise can boost memory.

"There is evidence at least in the short run that these kinds of lifestyle changes do have a significant effect on brain function, memory ability and different health measures that predict longevity, such as blood pressure and weight," Dr. Small says.

The new results, he adds, "reaffirm what many of us have been suspecting - that what is good for your heart is going to be good for your brain. And we all have more control than we think over aging."

Always consult your physician for more information.

Online Resources

Centers for Disease Control and Prevention (CDC)

National Institute of Mental Health

National Institutes of Health (NIH)

November 2004

Physical Activity Helps Prevent Mental Decline

Walking Lowers Dementia Risk

Exercise Benefits Heart, Too

What Is Dementia?

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What Is Dementia?

According to the National Institute on Aging, many older people worry about becoming more forgetful. They think forgetfulness is the first sign of Alzheimer’s disease. In the past, memory loss and confusion were considered a normal part of aging.

However, scientists now know that most people remain both alert and able as they age, although it may take them longer to remember things.

The NIA states that many people experience memory lapses. Some memory problems are serious, and others are not.

People who have serious changes in their memory, personality, and behavior may suffer from a form of brain disease called dementia.

Dementia seriously affects a person’s ability to carry out daily activities. Alzheimer’s disease is one of many types of dementia.

That is a message physicians and health officials are looking to promote during November, which is National Alzheimer's Disease Awareness Month.

The term dementia describes a group of symptoms that are caused by changes in brain function.

Dementia symptoms may include asking the same questions repeatedly; becoming lost in familiar places; being unable to follow directions; getting disoriented about time, people, and places; and neglecting personal safety, hygiene, and nutrition.

People with dementia lose their abilities at different rates. Dementia is caused by many conditions. Some conditions that cause dementia can be reversed, and others cannot.

The two most common forms of dementia in older people are Alzheimer’s disease and multi infarct dementia (sometimes called vascular dementia).

These types of dementia are irreversible, which means they cannot be cured.

In Alzheimer’s disease, nerve cell changes in certain parts of the brain result in the death of a large number of cells.

Symptoms of Alzheimer’s disease begin slowly and become steadily worse.

As the disease progresses, symptoms range from mild forgetfulness to serious impairments in thinking, judgment, and the ability to perform daily activities. Eventually, patients may need total care.

In multi infarct dementia, a series of small strokes or changes in the brain’s blood supply may result in the death of brain tissue.

The location in the brain where the small strokes occur determines the seriousness of the problem and the symptoms that arise.

Symptoms that begin suddenly may be a sign of this kind of dementia.

People with multi infarct dementia are likely to show signs of improvement or remain stable for long periods of time, then quickly develop new symptoms if more strokes occur.

In many people with multi infarct dementia, high blood pressure is to blame. One of the most important reasons for controlling high blood pressure is to prevent strokes. 

Always consult your physician for more information.