For well-functioning adults in their 70s, the ability to walk 400 meters (1/4 Mile) and the speed at which they walk are independent prognostic factors for mortality, cardiovascular disease and disability.
The "long-distance corridor walk" was developed as an alternative to treadmill testing in medically ill subjects, Dr. Anne B. Newman, from the University of Pittsburgh, and her associates note. They hypothesized that this test would also predict outcomes among older adults without known difficulty performing mobility-related tasks.
To test their hypothesis, they enrolled 3075 subjects ages 70 to 79 who were participating in the Health, Aging and Body Composition Study. The subjects were eligible if they reported that they could walk a quarter of a mile, climb a flight of stairs without resting, and perform basic activities of daily living (n = 2680).
The subjects were instructed to "walk as quickly as you can, without running, at a pace you can maintain." Thirteen percent of the eligible subjects did not complete the 400-meter walk, either because of fatigue, symptoms, or persistent tachycardia.
Surveillance was conducted every 6 months for an average of 4.9 years to determine incident cardiovascular disease (n = 308), persistent mobility limitation (unable to walk a quarter of a mile or climb stairs, n = 1116), disability (n = 509), or death (n = 351).
Multivariate adjustment for chronic health conditions, extent of long-term disease, cardiovascular risk factors, and lower extremity function showed that exclusion from or inability to complete the test were associated with higher risk for each outcome, with hazard ratios ranging from 1.17 to 1.95 when compared with subjects who completed the 400 meters.
Those who required longer time to complete the walk were also at higher risk than those who were quicker, with each additional minute associated with a 29% higher rate of mortality, 20% higher rate of cardiovascular disease, and 52% higher rates of mobility limitation and disability.
Thus, Dr. Newman’s team concludes that "this test may be useful in clinical practice for the identification of early decline in function." For those unable to walk 400 meters, they recommend "a short-course gait speed or short lower-extremity performance" to predict morbidity and mortality.
Learn about the Steps To Health, a program to increase physical activity that has gone through 8 years of clinical studies to show its effectiveness.
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