Doctors who are interested in measuring life expectancy may now have a simple way to do it - researchers have discovered that walking speed can be a useful predictor of how long older adults live.
Those who walked 1 meter per second (about 2.25 mph) or faster consistently lived longer than others of their age and sex who walked more slowly, the study showed.
"We're able to show that a person's capacity to move strongly reflects vitality and health," said study researcher Dr. Stephanie Studenski, a professor of medicine at the University of Pittsburgh.
However, the researchers also emphasized that the purpose of this study wasn't to get people to walk faster in hopes of living longer.
"Your body chooses the walking speed that is best for you, and that is your speed, your health indicator," Studenski said. "And that's what it really is: an indicator. Going out and walking faster does not necessarily mean you will suddenly live longer. You still need to address the underlying health issues."
The researchers showed they could reliably predict the 10-year survival rate of a group of people based on how fast they walked along a 4-meter track.
The walking speed for those with the average life expectancy was about 0.8 meters per second (about 1.8 mph) for most age groups of both sexes. Walking speed was a more accurate predictor of life expectancy than age or sex, the study showed.
The numbers were especially accurate for those older than 75. This suggests that for older people, walking speed could be a sort of "vital sign," like blood pressure and heart rate, the researchers said.
"When you think about it, a sick person would not have that certain spring in their steps. Therefore, it should not be surprising that walking speed can provide a simple glimpse into aging and health status," Studenski said.
The findings were based on analysis of nine previous studies that examined the walking speed, sex, age, body mass index, medical history and survival rate of almost 34,500 people.
The way we walk and how quickly we can walk depends on our energy, movement control and coordination, which, in turn, requires the proper functioning of multiple body systems, including the cardiovascular, nervous and musculoskeletal systems, Studenski told MyHealthNewsDaily. Because of this, researchers have associated walking speed with health in the past.
"But in the past, we simply knew that walking faster was better," said Dr. Matteo Cesari, who wrote an editorial accompanying the new findings, but was not involved in the study.
"This study provides us the numerical basis to estimate survival for each walking speed measured on an older person," Cesari said.
"When we measure, for example, blood pressure, we need a cut-off point to understand whether it is normal or not. Similarly, we now have a cut-off point to understand whether the overall health of a person is normal for his/her age by simply testing their walking speed," Cesari told MyHealthNewsDaily.
Studenski said this finding will have many practical applications. It is a quick and inexpensive way for seniors to gauge their own health. Similarly, doctors can monitor and remedy their patients' quality of life based on this. Walking speed, and in turn, mobility, will be a useful way to measure whether someone is still maintaining a healthy, active and independent lifestyle.
Older adults who walk faster than 1 meter per second may live longer than those who walk more slowly.livescience.com