See also: Walking for exercise.
Although everyone's pace typically slows with age, adults who have hypertension experience a steeper drop in walking speed than those who don't have high blood pressure. The decline occurs even in men and women who control their blood pressure with medication, according to research funded by the National Institutes of Health.
Changes in walking speed can indicate possible health problems and reduce the ability to remain independent, says University of Pittsburgh epidemiologist Caterina Rosano, M.D., senior author of the study, which appears in the March issue of the Journal of the American Geriatrics Society. "For example, when you cross a street, you have to make a lot of decisions that depend on how quickly you can walk. Do I have enough time to get across? Will I slip if I try to hurry? Will I fall? If you have these stressful thoughts every time you come to a corner," says Rosano, "you may decide to visit friends less often, you won't be as comfortable going to the grocery store by yourself and you won't get out as much."
The researchers looked at changes in walking speed of 643 men and women who were, on average, 74 years old when the study began. Participants included 350 people without high blood pressure and 293 who were already taking medication to control blood pressure or whose high blood pressure was diagnosed when they entered the study. Those with high blood pressure were divided into three groups: newly diagnosed, able to control the condition with medication, and unable to control the condition with medication.
The researchers periodically measured how long it took the men and women to walk 15 feet. At the start of the study, they averaged 2.2 miles per hour. Although all participants slowed down over 14 years of follow-up, speeds dropped 9 percent more for all three groups with high blood pressure.
"This intriguing finding suggests that there may be something going on in the body related to high blood pressure that affects walking speed," says epidemiologist Jean Olson, M.D., project officer for the Cardiovascular Health Study at the National Heart, Lung and Blood Institute, who was not involved in this research. "We can bring down blood pressure with medication but that [may not] affect the underlying process."
The researchers thought that brain, kidney or heart problems might account for the slowing, but neither MRI brain scans nor kidney and heart functions showed any correlation.
Until scientists identify the link between high blood pressure and walking speed, "maintaining a healthy lifestyle to prevent hypertension from developing is one of the most important things older adults can do," says Rosano.
Nissa Simon writes about health and science in New Haven, Conn.