Does Usual Walking Speed Predict Survival in Older Adults?

Once individuals achieve the age of 65, they are considered to be a ‘senior citizen.’ For most, Medicare and retirement planning come to the forefront of their consciousness around this time. Life expectancy at age 65 varies widely, and is based primarily around lifestyle, genetics, and current health status. We all know how important it is to avoid tobacco and sedentary lifestyle, consume a heart-healthy diet, keep a close eye on blood cholesterol, triglyceride, and glucose levels, as well as monitor resting blood pressure in order to avoid (or at least delay) future health problems. Regular check-ups are also a must in this regard.

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‍Over the past several years, it has become apparent that in addition to the factors mentioned above, usual walking speed is significantly associated with survival in older adults. In a study published by the Journal of the American Medical Association, nine existing studies were combined using 34,485 ambulatory older adults aged 65 years or older. About 60% of the participants were women, and there were a substantial number of African-American and Hispanic participants. At baseline, all participants completed a detailed health history and were asked to walk at their usual pace from a standing start. The most commonly used walk distance in the nine studies was 6 meters (about 20 feet). The average follow-up time was 12 years, during which time 17,528 total deaths occurred. The risk of death was then estimated per 0.1 meter/second faster walking speed.

Because many factors could ‘muddy the waters’ in this type of study, the researchers carefully accounted for age, smoking status, body mass index, resting blood pressure, race, presence of disease, self-reported health status, and length of follow-up. Even after taking all of these factors into account, usual walking speed remained a significant predictor of death! More specifically, there was an approximate 10% decreased risk of death per 0.1 meter/second faster walking speed.

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As an example, those who walked 1.1 meters/second were about 20% less likely to die during follow-up compared to those who walked 0.9 meters/second. At this point, you are probably wondering how walking speed in meters/second translates to walking speed in miles per hour. The chart below provides this information.

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To summarize, after taking a number of other variables into account, usual walking speed was a strong predictor of mortality in older adults. Should you wish to administer this test to someone, here are the procedures (you may also test yourself if you wish):

Materials Needed: A level and smooth not-slip surface, stopwatch that can record to the nearest hundredth of a second, colored tape, tape measure.

Procedures: Place two pieces of tape 6 meters (19 feet, 8 inches) apart. These will be the start and finish lines. The participant will be in a standing position. Before the test begins, instruct the participant to walk the 6-meter distance at their normal walking speed, as if they were walking down the street. The test administrator will stand at the finish line and say ‘ready, set, go,’ start the stopwatch on ‘go’, and stop the watch as the participant crosses the finish line. No further instructions or encouragement should be given following the ‘go’ command.

Scoring: Divide 6 meters by the time in seconds to obtain walking speed. For example, if the participant walks 6 meters in 3.96 seconds, then their walking speed is 1.5 meters per second. Using the chart above, this translates to 3.4 miles per hour.

Just as a reminder, the Physical Activity Guidelines for Americans recommend accumulating at least 150 minutes per week of moderate intensity aerobic activity such as brisk walking. More is better to a point, especially if weight loss is a goal. However, if you are just getting started on a walking program, keep in mind that it may take a few weeks to gradually build up to meeting the guidelines.  

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Reference

Studenski, S., et al. (2011). Gait speed and survival in older adults. JAMA. 305(1):50-58.