Slow walking may not only mean getting to your destination later, according to a new study by French scientists: Older people who walk slowly are almost three times more likely to die of heart disease and related causes than older people who walk faster.

“The main message for the general population is that maintaining fitness at older age may have important consequences and help preserve life and (muscle) function,” one of the study’s authors, Dr. Alexis Elbaz, director of research at the Paris-based medical research institute Inserm, told Reuters Health by email.

He said the study, which appeared in the journal BMJ, also suggests that a test of walking speed might be used to test the health of elderly patients.

Previous studies had linked slow walking speed with increased risk of death over a given period, as well as with falls and other bad health outcomes, but hadn’t shown whether it was heart disease or another cause that accounted for that higher risk.

The five-year study, part of Inserm’s ongoing Three City Study, involved more than 3,200 relatively fit men and women, 65 to 85 years of age, living in three French cities. At the start of the study in 1999, the scientists used questionnaires and face-to-face interviews to assess the health of each participant. They then clocked the participants’ speeds as they walked down a corridor as fast as possible without running.

Over the next five years, 209 of the participants died - 99 from cancer, 59 from heart disease, and 53 from infectious diseases and other causes - for an overall death rate of almost 7 percent. The death rate among the slowest-walking one-third of participants - those men who walked at the equivalent of about 3.4 miles per hour or slower and women who walked at about 3 miles per hour or slower - was 44 percent higher than that among the two-thirds of participants who had walked faster.

Death from heart attack, stroke, and related causes was 2.9 times more common among the slowest one-third of participants than among the participants who had walked faster.

The increase in death from heart disease was seen in both men and women and was unrelated to the ages of participants or how physically active they were.

The researchers found no connection between walking speed and other causes of death, including cancer.

What explains the link between slow walking speed and death from heart disease? One possibility, Elbaz told Reuters Health in an email, is that the same risk factors that raise heart disease risk - high blood pressure and diabetes, in particular - also cause “silent strokes” that make it hard to walk fast. This idea “deserves additional studies to be confirmed,” he wrote.

In an accompanying editorial, Dr. Rowan H. Harwood of Queen’s Medical Center in Nottingham, England, and Dr. Simon P. Conroy of the University of Leicester, also in England, said that slow walking can be caused by problems in a number of body systems, from bones to muscles to lung and the brain. Some of those are linked by blood vessel problems, and by smoking.

SOURCE: BMJ, published online November 11, 2009.