Your walking speed may predict your life span

"This paper is a monumental effort in data analysis to come up with exact numbers and predictors in terms of the relationship between gait speed and survival," says Dr. Farzaneh Sorond, a stroke neurologist at Brigham and Women’s hospital who studies gait speed in the elderly but wasn't involved in this study.

While Sorond says she typically observes how her patients walk during her assessments, she never measured their speed. "With this new information, I'd think seriously about implementing gait speed as part of a routine assessment."

The researchers found that the usual walking pace of those over 65 varied from less than 1.3 feet per second over 13 feet -- which carried the highest death risk -- to more than 4.6 feet per second, which was associated with the lowest risk. Sorond says she can use this information to advise her patients.

"If they fall into the fast super-performer group, I can tell them they have a pretty good chance of outliving their peers," she says. On the flip side, those who walk the slowest might need more aggressive interventions to treat underlying medical conditions that cause gait to slacken through the years.

But therein lies the rub. Perhaps the increased death risk comes from serious medical conditions -- like Parkinson's, multiple organ failure, and severe vascular disease -- all of which can slow walking speed and, in their own right, lead to shorter lives.

That's true, acknowledge the study researchers, but that's also the point. They write that gait speed could be considered a reliable way to access vitality "because it integrates known and unrecognized disturbances in multiple organ systems."

For many elderly folks who walk slowly, hitting the treadmill at the gym to improve their fitness level isn't the solution. "We need to do more to figure out what slows gait speed," Sorond acknowledges. "It's a complex process."

On the other hand, if you're just starting to slow down a bit and don't have major medical problems, getting that exercise may be the key to a longer life, Sorond contends. "I’m sure a 70-year-old marathoner has a faster gait than the average person, and we know that good physical fitness is an important predictor of life expectancy."