Is prescribed exercise in older people beneficial? The answer: a resounding "maybe"

As Medicine continues its journey to become more “evidence-based” it is humbling to realize how little we really know about prescribed treatments.  A case in point:  Is it good to exercise?  In both health and disease?  As we age?  Dr. Marco Pahor and his colleagues contributed one more brick in the wall of evidence in a recent research paper in JAMA.  The short answer -- probably. 

 

Their paper (Effect of Structured Physical Activity on Prevention of Major Mobility Disability in Older Adults, JAMA 2014;311,(23):2387-2396) attempts to systematically address a fundamental question: Does exercise help prevent or delay loss of mobility in older adults?  This was a well-designed trial.  The patients represented a good cross section of the population, geographically and ethnically.  They were typical people, like those seen in a primary care physician’s office: average age 79, obese, sedentary with multiple chronic health conditions (e.g. hypertension, diabetes, cancer).  The follow up period was adequate to detect some longer-term impact of the intervention (average 2.6 years).

The intervention was something the average person could reasonably replicate.  Participants walked a total of about 2 ½ hours a week, supplemented by brief sessions of strength training (using ankle weights) and stretching of large muscle groups.  It is a program you could actually envision a motivated patient performing.  A control group was given general health education classes (plus a little light stretching).  Over 1600 patients were randomized to the two groups.

The primary outcome measure was simple.  All the participants could walk 400 meters (about ¼ mile) upon entry to the study.  Did they maintain or lose that ability during the course of the project?

Results?  At the end of the study period, 30.1% of the exercise group lost the ability to walk 400 meters.  People in the control group (education only) lost this ability 35.5% of the time.  The results were statistically significant.  So, the answer to the question is affirmative.  Exercise does help elderly patients maintain mobility.

So do we now have evidence to support widespread prescription of exercise to octogenarians? Nothing in medicine is so simple.  Taking nothing away from an excellent and important study, it answers some questions, but raises others.

The impact or exercise is statistically significant, but is it compelling enough to zealously prescribe exercise? Compliance with exercise is not an easy task, even in the young and healthy.  If you were told: “you have a 35% chance of seeing your mobility decline in the next couple of years, but we can reduce that risk to 30% with a long-term structured exercise program” is that a compelling enough effect to motivate you to strap on your gym shoes?  Taking the data from the study, a physician would need to convince 23 previously sedentary people to begin an exercise regimen, and those 23 would need to be compliant with the program, to prevent one person from losing mobility.

The study also looked at some secondary outcome measures, including the need for hospitalization, and the occurrence of “serious adverse events” like heart attacks, strokes, or death.  The trend for both was negative.  Hospitalizations and adverse events increased in the exercise group, but in neither case did the effect reach the level of statistical significance.   Had these trends been significant, it would have created an interesting conundrum…exercise would be good for maintaining function, but could actually increase health care costs.

In summary, this study adds to a growing literature to prove what many might think is intuitively obvious: exercise has positive health benefits.  Enough to justify, from an evidence based medicine perspective, a major public health investment?  Enough to drive down health care costs? Probably not. 

Enough to convince you, as an individual to stay as active as you can, for as long as you can.  Absolutely.