Walking speed could be a new indicator of health

Walking speed is making strides toward becoming a key metric of a person's health with the launch of the 6th Vital Sign, a first-of-its kind study being conducted by the Duke Clinical Research Institute (DCRI). 

06 may 2016--The Duke research team is asking volunteers to download a free ResearchKit app from the Apple iTunes store, answer some questions and then take a two-minute stroll. The app securely uploads walking speed captured on a phone along with demographic data to calculate a reliable and personalized health measure.
"Walking speed is recognized, yet underutilized, as a measure and predictor of a person's health. It can be used as a vital sign much like blood pressure, temperature, heart and breathing rate and pain," said study team leader Janet Prvu Bettger, ScD, an associate professor and director of health policy and implementation science in Duke's Department of Orthopaedic Surgery.
Vital signs measure the body's basic functions and should be easy to measure at home, in a hospital or at a health clinic. "Mobility, or a person's ability to move, reflects the health of all of our body's systems," Bettger said. On the other hand, immobility impacts a person's muscles, heart, digestive system, joints, and even mood.
"As a 6th Vital Sign, walking speed can be used to track a person's recovery from illness or injury, declines in health, or even risks for falls, or depression," Bettger said. "Among older adults we know that walking speed can even be used to predict survival."
The 6th Vital Sign study is designed to:

• Create walking speed norms based on mobile phone rather than clinic measures.
• Develop walking speed comparison charts by age and gender for all adults (like height and weight charts).
• Create maps of how walking speed varies by where people live.
• Increase awareness of the importance of walking speed.
• Make walking speed a vital sign used in homes, health care and communities around the globe.

"We are very excited by the possibilities of mobile apps such as the 6th Vital Sign to reach large cross-sections of the population and stimulate healthy behaviors," said DCRI Executive Director Eric Peterson, M.D. "DCRI is committed to evaluating how we can use innovative mobile technologies in research as well as in promoting population health in general."
To participate in the study, adults are being asked to download the 6th Vital Sign mobile app free from the iPhone Store, answer a few questions, and take a two-minute walk. Anyone living in the United States, over the age of 18, and with access to an iPhone 5s, 6, or 6 plus can join the study. (This is an iPhone-only and English language study at this time.) Participants will receive feedback on their walking performance compared to others their age and gender and can save or share their results. Participants can complete the walk test more than once and monitor their status over time to learn more about their own personal walking speed.
"We're conducting this study because we don't know enough about the walking speed across the human lifespan," said Miriam Morey, Ph.D., a professor of medicine and senior fellow in the Center for the Study of Aging and Human Development at Duke.
"As we get older, our systems start to decline and we have age-related declines that are normal," Morey said. "However, we can influence the pace of this decline by how we take care of ourselves. Right now, we don't routinely measure walking and strength so we don't know what's going on – or what we need to be doing. The 6th Vital Sign study examines a new approach to be measuring mobility."
"This research app allows us to create new mobile-phone based standards and norms for walking speed for people, first around the U.S. and eventually around the world," Bettger said. "The more people who participate in the study, the more representative our findings. This will help us create more accurate predictions of future health and measure-based action plans to promote health, recovery from an injury, and prevention of falls. And because smart phones are so common among people of all ages, there is a great potential to engage an unlimited population in research and create new knowledge for entire populations."


Provided by Duke University

Walking speed associated with survival in older adults

In an analysis that included data from 9 studies, having higher measures of walking speed among older adults was associated with increased length of survival, according to a study in the January 5 issue of JAMA.

05 jan 2011--"Remaining years of life vary widely in older adults, and physicians should consider life expectancy when assessing goals of care and treatment plans. However, life expectancy based on age and sex alone provides limited information because survival is also influenced by health and functional abilities," according to background information in the article. There are currently no well-established approaches to predicting life expectancy that incorporate health and function. Gait speed, or walking speed, has been recommended as a potentially useful clinical indicator of well-being among older adults.

Stephanie Studenski, M.D., M.P.H., of the University of Pittsburgh, and colleagues conducted a study to assess the association of gait speed with survival in older adults and to determine the degree to which gait speed explains variability in survival after accounting for age and sex. The study included a pooled analysis of 9 participating studies (collected between 1986 and 2000), using individual data from 34,485 community-dwelling adults age 65 years or older with walking speed data available at the beginning of the study, followed up for 6 to 21 years. Participants had an average age of 73.5 years; 59.6 percent were women; and 79.8 percent were white. Gait speed was calculated for each participant using distance in meters and time in seconds. All studies used instructions to walk at usual pace and from a standing start. The walk distance varied from 8 feet to 6 meters. The average gait speed of the participants was 0.92 meters (3 feet) per second.

During the course of the study, there were 17,528 deaths. The overall 5-year survival rate was 84.8 percent; the 10-year survival rate was 59.7 percent. The researchers found that gait speed was associated with differences in the probability of survival at all ages in both sexes, but was especially informative after age 75 years. At this age, predicted 10-year survival across the range of gait speeds ranged from 19 percent to 87 percent in men and from 35 percent to 91 percent in women.

"Predicted years of remaining life for each sex and age increased as gait speed increased, with a gait speed of about 0.8 meters [2.6 feet]/second at the median [midpoint] life expectancy at most ages for both sexes. Gait speeds of 1.0 meter [3.3 feet]/second or higher consistently demonstrated survival that was longer than expected by age and sex alone. In this older adult population the relationship of gait speed with remaining years of life was consistent across age groups, but the absolute number of expected remaining years of life was larger at younger ages," the authors write.

The researchers also found that predicted survival based on age, sex, and gait speed was as accurate as predictions based on age, sex, use of mobility aids, and self-reported function or as age, sex, chronic conditions, smoking history, blood pressure, body mass index, and hospitalization.

The authors suggest there are several reasons why gait speed may predict survival. "Walking requires energy, movement control, and support and places demands on multiple organ systems, including the heart, lungs, circulatory, nervous, and musculoskeletal systems. Slowing gait may reflect both damaged systems and a high energy cost of walking."

The researchers write that there are a number of ways gait speed might be used clinically, including helping to identify older adults with a high probability of living for 5 or 10 more years, who may be appropriate targets for preventive interventions that require years for benefit. Gait speed might be used to identify older adults with increased risk of early mortality, perhaps those with gait speeds slower than 0.6 meter (2 feet)/second. "In these patients, further examination is targeted at potentially modifiable risks to health and survival." Also, gait speed might be monitored over time, with a decline indicating a new health problem that requires evaluation.

"The data provided herein are intended to aid clinicians, investigators, and health system planners who seek simple indicators of health and survival in older adults. Gait speed has potential to be implemented in practice, using a stop watch and a 4-meter [13 feet] course. From a standing start, individuals are instructed to walk at their usual pace, as if they were walking down the street, and given no further encouragement or instructions. The data in this article can be used to help interpret the results. Gait speed may be a simple and accessible indicator of the health of the older person," the authors conclude.

More information: JAMA. 2011;305[1]:50-58.

Provided by JAMA and Archives Journals

For Older Walkers, Faster Is Better

13 nov 2009-- Highlighting the importance of staying fit in old age, a French study has found that seniors who walk slowly are three times more likely to die from cardiovascular disease than are fast walkers.

The researchers measured the walking speed of the participants -- 3,208 men and women, ages 65 to 85 -- and collected medical and demographic information on them at the start of the study. Follow-up exams were performed at regular intervals over the next five years.

After adjusting for a number of baseline characteristic, the researchers found that seniors with the slowest walking speed were 44 percent more likely to die than the fastest walkers. The slowest walkers also had a three-fold higher risk of cardiovascular death.

The increased risk of cardiovascular death was found in both women and men, in younger as well as older seniors and in those with low or usual physical activity levels.

There was no link between walking speed and risk of death from cancer.

"These findings show that assessment of motor performances in older people using simple measures such as walking speed can be performed easily and that the role of fitness in preserving life and function in older age is important," the researchers wrote.

The study was published online Nov. 10 in BMJ.