Has your gait become slower at the age of 45?
Scientists say the speed at which people walk in their fifties is a sign of how rapidly their brains, as well as their bodies, are aging.
Using a simple walking speed test, the researchers were able to measure the pace of the aging process.
Not only did the slow walkers have a faster aging body, their faces looked older, and they had smaller brains.
The international team of researchers said the results were an "amazing surprise".
According to the BBC, "doctors often use walking speed as a measure of general health, especially in people over the age of 65, because it is a good indicator of muscle strength, lung function, balance, spine strength and eyesight."
Scientists have also linked slowed walking to an increased risk of dementia and poor health.
This study was conducted on about 1,000 people in New Zealand, born in the seventies of the last century and followed from an early age until the age of 45 years.
These people underwent physical exams, brain function tests, accurate brain scans, a measure of walking speed, and, during their childhood, cognitive tests every two years.
Study leader Professor Terry E. Moffitt, who works at King's College London and Duke University in the United States, said: "The study revealed that slow walking is a sign of a problem, a finding that predates age by decades.
As the subjects reached the age of 45, there was a wide variation in walking speeds, with the fastest walking at two meters per second without running.
Signs of "accelerated aging" were generally seen in those who walked slowly, as their lungs, teeth and immune system deteriorated more than in those who walked the fastest.
The most surprising finding was that brain scans showed that slower walkers were more likely to have an older brain.
The researchers found that 45-year-olds could predict walking speed using the results of IQ, language and motor skills tests taken at the age of three.
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signs of aging