Physical Fitness and Chronic Disease Prevention
In the most upcoming issue of the Archives of Internal Medicine (Sept 24, 2012), there is an article by Dr. Benjamin L. Willis and colleagues called “Midlife Fitness and the Development of Chronic Conditions in Later Life”. Their findings lend more support to the idea that being more active helps prevent chronic conditions.
It was an impressive article in that they made use of a large cohort of subjects–18,670 total– that took a physical fitness test at one point in time in middle age (average age 49 years old). They then looked at how many chronic diseases, through Medicare data, these people developed and when. They found that people who were most active, compared to the least active, were less likely to develop chronic diseases. Furthermore, when they did develop a chronic disease, they developed them later in life. This is support for what is referred to as compression of morbidity, which is the phenomenon that now that people live longer, much of the morbidity of disease is also being compressed into fewer years toward the end end of life, so that overall we live longer, less-sick lives.
Some of the specifics– They considered people’s physical fitness by a treadmill test and measured their fitness by “metabolic equivalents” (METs; a measure of intensity of activity). They looked at 8 chronic diseases: ischemic heart disease, congestive heart failure, stroke, diabetes, chronic obstructive pulmonary disease, chronic kidney disease, Alzheimer’s, and cancer of the colon or lung. They report that for each increase in MET, men had a 5% lower risk of developing a chronic disease and women had a 6% lower risk of developing a chronic disease. And this was true when they looked at each of the diseases on their own, meaning more activity protected against all of these various conditions. (For reference: sitting watching TV is ~1MET, walking is ~3 METs, and running ~7-8 METs.)
They say that exercise did not appear to extend lifespan, but those who died had fewer chronic conditions before they did. And, of course, there were several potential problems with the study. There were more men(~80%) then women, and this was overall a white, well-educated group– so this is not representative of our country as a whole. They also cannot really say if people workout more and can attribute good health to that, if they workout more because they are fundamentally more healthy, or if they are healthier and workout for a third, but related, reason (like maybe good genes?).
Overall, this was an intriguing study and lends support the idea that activity is good for us and means we will live healthier lives, from middle age onward. Not many of us will waste much time arguing this– we would rather spend it being active!
The article: http://archinte.jamanetwork.com/article.aspx?articleid=1352789
Interview with the author, Dr. Benjamin Willis: http://archinte.jamanetwork.com/multimedia.aspx
Commentary in the same issue, “Thriving of the Fittest”: http://archinte.jamanetwork.com/article.aspx?articleid=1352790
NY Times article about the research: http://well.blogs.nytimes.com/2012/09/05/the-benefits-of-middle-age-fitness/