New study claims how quickly you can take a step reveals how long you'll live
Taking a step is something most of us do without giving it a second thought, but a new study suggests the speed at which we do it could actually be a window into how long we've got left.
For younger people, or those without any movement issues, walking is about as automatic as it gets.
But as we age, scientists believe the time it takes to put one foot in front of the other might offer a genuine clue when it comes to measuring lifespan and assessing the risk of death.
Researchers from Ben-Gurion University of the Negev (BGU) wanted to better understand how balance, posture and muscle movement were linked to survival rates in older adults, and tracked a group of participants over the course of nearly two decades to find out.
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What they discovered has some fairly significant implications for how doctors might assess older patients in future, and it all comes down to a single, often-overlooked movement.
How does step speed predict how long you'll live?
The study, led by Professor Itshak Melzer from BGU's Department of Physical Therapy alongside colleagues from BGU, Soroka University Medical Center and the University of Minnesota, found that for every extra 100 milliseconds, or one-tenth of a second, it took participants to begin a voluntary step while distracted, their risk of death increased by 28 percent over the course of the research period.
To reach this conclusion, the team tested participants under two different conditions.
The first was a simple single-task setup, where they were asked to step as quickly as possible following a cue. The second was a dual-task condition, which required them to execute the same rapid step while simultaneously performing a modified Stroop task, naming the ink colour of words printed in mismatched colours.
Because basic nerve conduction speeds stay constant regardless of distraction, researchers say any extra delay seen during the dual-task condition comes down to limitations in central neural processing, meaning the brain is essentially struggling to multitask between thinking and moving.
The team also tested static balance by measuring how much participants swayed while standing barefoot with their eyes closed, and found this could predict mortality too, though it proved considerably less accurate than the dynamic stepping tests.
The researchers believe slower steps may point to broader neurological and physiological resilience in older adults, effectively signalling how well the brain and body are able to adapt to stress as they age. This matters because poor balance significantly raises the risk of falls, which can in turn lead to broken bones, muscle wasting and even traumatic brain injuries.
"Incorporating dual-task based assessments into standard clinical evaluations could significantly improve survival prediction and help guide early interventions targeting cognitive-motor health," the study's authors concluded.
Why does walking speed slow down as we get older?
Walking speed naturally declines with age as a result of muscle weakness, reduced joint flexibility, weaker balance and slower brain processing.
Calf muscles and fibres degrade over time, for example, which causes older people to take shorter steps and ultimately slows down their overall pace.
Nerve signals in the areas of the brain responsible for motor function also tend to suffer delays as we age, resulting in miscommunication between the brain and the muscles.
For the study, published in the journal Gerontology, researchers recruited 120 community-dwelling adults over the age of 65, who were then tracked for between 10 and 17 years following their initial testing.
Participants who did not survive the study period took noticeably longer to initiate a step than those who did, with the gap widening further under distracted conditions.
Crucially, the researchers note that step initiation speed isn't necessarily fixed.
Previous clinical trials have shown the trait can actually be improved through targeted perturbation and balance rehabilitation training, suggesting the test could eventually be used to identify which patients might benefit most from mobility programmes designed to extend their long-term health.
There were some limitations to the study, including its relatively small sample size and the fact that participants were only tested under one set of experimental conditions.
The researchers also stressed that the findings show an association rather than a confirmed direct cause.
Thomas Bamford