The speed with which people walk in their forties is a sign of the aging of their brains, as well as their bodies, scientists have suggested.
With the help of a simple walk speed test, researchers were able to measure the aging process.
Not only did the body of slow walkers age faster, but their faces looked older and their brains smaller.
The international team said the results were an "amazing surprise".
Doctors often measure gait speed to assess general health status, especially in those over 65, as this is a good indicator of muscle strength, lung function, and Balance, strength of the spine and sight.
Slowing gait speed in the elderly has also been associated with a higher risk of dementia and decline.
In this study, out of 1,000 people in New Zealand – born in the 1970s and followed up until the age of 45 – the walking speed test was used much earlier, on adults in mid-life.
Study participants also took physical tests, brain function tests and brain tests. During their childhood, they passed cognitive tests every two years.
"This study revealed that a slow walk is a sign of trouble decades before age," said Professor Terrie E. Moffitt, lead author of King's College London and the University of Toronto. 39; Duke University in the United States.
Even at the age of 45, walking speed varied considerably, with the maximum speed being 4 m / s at top speed (without running).
In general, the slowest walkers tend to show signs of "accelerated aging", their lungs, teeth and immune system being in worse condition than those who walk faster.
The most unexpected finding was that brain scans showed that slow walkers were also more likely to have an older-looking brain.
And the researchers found that they were able to predict the walking speed of 45-year-olds by using the results of their three-year-old intelligence, language, and motor skills tests.
Children who grew up to be the slowest walkers (averaging 1.2 m / s) averaged 12 points lower IQ than those who walked the fastest (1.75 m / s) 40 years later.
The international team of researchers, writing in the JAMA Network Open, said the differences in health and IQ might be due to lifestyle choices or to the fact that some people were healthier at the beginning of their lives. their life.
But they suggest that there are already early signs of life that will come out better in terms of health later on.
The researchers said measuring walking speed at a younger age could be a way to test treatments to slow down human aging.
A number of treatments, from low-calorie diets to metformin intake, are currently under study.
It would also be an early indicator of brain and body health so that people can change their lifestyle while being young and healthy, the researchers said.