Slower walking with increasing age has always been a warning sign of increasing fragility, which could lead to falls and other disabilities, experts say. Evolving research on small groups of older subjects has also found that slower walking year after year can be an early sign of cognitive decline.
According to studies, this may be due to a shrinking of the right hippocampus, which is the part of the brain associated with memory.
But not all signs of cognitive decline predict later dementia – according to the National Institute on Aging, only 10 to 20 percent of people aged 65 or older with mild cognitive impairment or MCI will develop dementia within the next year.
“In many cases, the symptoms of MCI may remain the same or even improve,” the institute said.
A large-scale new study of nearly 17,000 adults over the age of 65 has found that people who walk about 5 percent slower or more each year and show signs of slower mental processing are most likely to develop dementia. The study was published Tuesday in the JAMA Network Open.
“These results emphasize the importance of walking in assessing the risk of dementia,” wrote corresponding author Taya Collyer, a researcher at the Peninsula Clinical School at Monash University in Victoria, Australia.
“Double rejectors” with the highest risk
The new study looked at a group of Americans over the age of 65 and Australians over the age of 70 for seven years. Every other year, people in the study were asked to undergo cognitive tests that measured overall cognitive decline, memory, processing speed, and verbal fluency.
Twice every two years, subjects were also asked to walk 3 meters or about 10 feet. These two results were then averaged to determine a person’s typical gait.
At the end of the study, the researchers found that the highest risk of dementia was in “dual decayers”, or people who not only walked more slowly but also showed some signs of cognitive decline, said Dr. Joe Verghese, Professor of Geriatrics and Neurology. at the Albert Einstein College of Medicine in the Bronx, New York, who did not attend the study.
“In addition, dual dementia had a higher risk of dementia than those who only have walking or cognitive decline,” Verghese wrote in an accompanying editorial published in JAMA magazine on Tuesday.
A double link between walking speed and memory decline predicts later dementia, a meta-analysis by 2020 found nearly 9,000 American adults.
Despite these findings, “gait dysfunction was not considered an early clinical feature in patients with Alzheimer’s disease,” Verghese wrote.
There are things we can do as we age to reverse the shrinking brain that comes with typical aging. Studies have found that aerobic exercise increases the size of the hippocampus and increases some aspects of memory.
The hippocampus, buried deep in the temporal lobe of the brain, is a special-shaped organ that is responsible for learning, consolidating memories, and spatial navigation, such as the ability to remember direction, location, and orientation.
Aerobic exercise increased right anterior hippocampal volume by 2 percent, reversing an age-related organ loss by one to two years in a 2011 randomized clinical trial. In comparison, people who did only stretching exercises experienced a decrease of approximately 1.43 percent.
Aerobic exercise means “air” and is a type of training in which your heart rate and breathing speed up, but not so much that you can no longer function. Types of aerobic exercise can include brisk walking, swimming, running, cycling, dancing and kickboxing, as well as all the cardio machines in your local gym, such as a treadmill, elliptical trainer, rower or stair climber.
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