Letting your patients know how long they may survive and how to extend their survival time can get your patients to increase their physical activity or get them to start.
Studies show that past age 65, your walking speed at your natural pace is a surprisingly reliable predictor of survival. Measuring gait speed over a short distance, such as across a room (13 feet or 4 meters) is a useful tool for doctors to set appropriate treatment and care goals for aging individuals.
A large study looked at the natural gait speed of 34,485 participants ages 65 and older from nine previous studies. These studies followed outcomes for 12 years or more, in which time almost half of the participants died. They found a consistent effect of how long people lived and whether they had a faster or slower gait speed:
- Those who walked at 2.2 miles per hour (27:16 minutes per mile or 1.0 meter per second) or faster were likely to live longer than would be predicted by age and sex alone.
- Those who walked at 1.8 miles per hour (33:30 minutes per mile or 0.8 meters per second) were likely to live the average lifespan for their age and gender.
- Those who walked at 1.3 miles per hour (46:09 minutes per mile or 0.6 meters per second) were at greater risk for early mortality.
- Shorter than expected lifespans were seen for those who walked slower and slower speeds.
The study included a large sampling of age, sex, race/ethnicity, and other subgroups and the median survival of all of the participants resembled that of the U.S. adult population at large. They noted that there could be some biases common to studies that recruit healthy volunteers, such as enrolling fewer people with advanced dementia.
The researchers noted that just because a person walks very slowly, it doesn’t mean that they won’t still live a normal or even increased lifespan. That would depend on the individual.
Knowing that your patient understands that by making small changes to their physical activity can extend their lives in older age, knowing how much longer they are likely to survive can be a factor in getting them to be more aggressive in treatment decisions or undergo a surgery that requires a long rehabilitation period if they think they have decades left to live.
There are many reasons that people walk slower in older age. Walking is a complex activity that is affected by changes to numerous systems of the body. You might naturally think about arthritis affecting your hips and knees as slowing your pace. But you also must have lungs and heart that are in good working order. Your brain and nervous system must function well to send messages to the muscles so they work in a coordinated fashion and to maintain posture and balance as you walk.
The participants in the studies that produced these results didn’t know that their walking speed was something significant, so they were unlikely to be trying to walk faster than normal. You may try to use a treadmill and note the speed that feels comfortable and natural to you to compare a speed measured walking for 13 feet. To use the 13-feet walking test, you would divide the number of seconds by 4 to get the meters per second.
The researchers produced a table and graphs for men and women that show how the median life expectancy varies over a range of walking speeds. These are shown in meters per second. For a 13-foot walk, you would take the number of seconds to complete it and divide it by 4 to get meters per second. If you time your walk by other means, here is how those numbers translate:
- 0.2 meters per second: 0.4 miles per hour or 300 minutes per mile
- 0.6 meters per second: 1.3 miles per hour or 100 minutes per mile
- 0.8 meters per second: 1.8 miles per hour or 33:30 minutes per mile
- 1.0 meters per second: 2.2 miles per hour or 27:16 minutes per mile
- 1.1 meters per second: 2.5 miles per hour or 24 minutes per mile
- 1.4 meters per second: 3.1 miles per hour or 19:21 minutes per mile
- 1.6 meters per second: 3.6 miles per hour or 16:40 minutes per mile
This research doesn’t prove cause and effect. However, improving physical fitness is associated with living a longer life. In addition to aerobic activity, muscle-strengthening activities should be incorporated into daily living two or more days per week. For patients who are at risk for falling, exercises that maintain or improve balance are recommended.
For patients with a chronic condition that doesn’t allow moderate-intensity aerobic activity, they should simply try to be as physically active as their abilities allow.
- Improving physical fitness is associated with living a longer life.
- Improving physical fitness can improve quality of life.
- Patients should be as physically active as their abilities allow safely.
Physical Activity Guidelines for Americans, Chapter 5: Active Older Adults. HHS Office of Disease Prevention and Health Promotion. https://health.gov/paguidelines/guidelines/chapter5.aspx.
Studenski S, Perera S, Patel K, et al. Gait Speed and Survival in Older Adults. JAMA : the journal of the American Medical Association. 2011;305(1):50-58. doi:10.1001/jama.2010.1923.