Wednesday, January 23, 2013

Walking Rate Correlated to Life Expectancy

Photo by will wilson
Doctors measure vital signs of body temperature, heart rate, blood pressure, and respiratory rate as  quick-yet-valid indicators of general health.  Other common measures include oxygen saturation, pupil state, glucose levels, pain level, and emotional state.

Physical therapists and other medical experts are proposing walking speed as another significant vital sign.

In 2009, Stacy Fritz & Michelle Lusardi published a white paper in the Journal of Geriatric Physical Therapy, arguing that doctors should start regularly assessing rate of walking in their patients. Research they cite shows that gait speed correlates closely with life expectancy.  The authors explain that a person's walking speed requires that a number of mental and physical systems operate adequately:

"These include, but are not limited to, an individual's health status, motor control, muscle performance and musculoskeletal condition, sensory and perceptual function, endurance and habitual activity level, cognitive status, motivation and mental health, as well as the characteristics of the environment in which one walks."

In the brief video below, JAMA (Journal of American Medical Association) provides an overview of a study published in 2011 that compiled data for walking speed and longevity for nearly 35,000 older adults.

For a summary (written for a lay audience) of the 2011 JAMA study see this article in Scientific American. 

If a person's walking speed suddenly slows down, he or she should work with a physician to discover the underlying cause. For example, slowing walking speed can be a sign of heart problems or a sign of oncoming dementia.   The root cause for a slowing gait might be something that can be treated and reversed.

So what is the normal walking speed for a person 65 plus?  Research shows that the normal walking speed for older adults exists between 1.8 and 2.7 miles per hour (or 1.2 to 1.4 meters per second).  But if a person drops below that speed, simply walking faster doesn't necessarily reverse the physical or cognitive problem that is the root cause. 

For example, if you have a blocked artery, you will have shortness of breath and walk slower. Pushing yourself to walk faster will not clear an artery that's already blocked. In fact, overexerting yourself could traumatize a weakened heart.  Walking daily for decades prior (along with maintaining a heart-healthy diet, refraining from smoking, and limiting stress) might have prevented the blocked artery. But once it's blocked, the person needs to see a cardiologist not a personal trainer. 

If a slow gait persists after treatment, this can be an indicator that additional support might be soon required for meeting activities of daily living.  Noting this sign can give a person and their loved ones time to help survey possible strategies for support: redesign of a home with ramps and grab bars, hiring a home health aid for some tasks, or a planning a move to a single-level home or to an assisted living facility. 

In the mean time, if you are free of cognitive and physical problems that might hinder walking speed, celebrate by logging off the computer and taking a walk around the block.   Work with your physician to design a diet and a fitness program to help you maintain good health for decades to come. 


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