"Runners are Far Ahead in Aging Healthfully"

NY Times 10/12/94

The NY Times article seems to correspond well with the original study in
the Annals of Internal Medicine. The major issue to get across, was that
regular vigorous exercise helped maintain a healthy body and slow down some
of the processes associated with aging. The article states that runners
"were leaner, had fewer medical problems and fewer joint symptoms, took
fewer medications and were less likely to have experienced previous
disability that were the non-runners."

At the beginning of the study, the runners (ever-runner and runner's
club) seemed to be in better health than the non-runners. This points
to one possible weakness in the research which is detailed in the
Times article: "the initial health differences could reflect the fact
that people in good shape initially are more likely to choose to be
vigorously active." Like self-selection bias, this is a possible
confounding variable, which skewed the results. The researchers also
concede that "because this study was an observational comparison of
self-selected groups without an externally imposed intervention, it
could not determine whether the community controls could be made as
healthy as the runners by instituting a more rigorous exercise
program." This however, is endemic to many studies of this type; we
find that there perhaps is a high correlation between health and a
particular practice, but in this study, it would not be possible to
have a longitudinal study of another 12 years or so, simply because of
carry-over effects.  One other issue that puzzled me was a discrepancy
in the variables measured before and after.  Initially, a whole array
of physiological measures were tabulated, but the data at the end of
the study reflects only a partial list of the initial criteria.
Therefore, I was confused as to what measures were truly important,
how and why they reduced the number of variables and what this could
mean to their overall interpretation of the results.

Overall, the findings are interesting, but not surprising. It has long
been assumed that one's health is determined by nature, the
environment and lifestyle. We are more able to alter lifestyle than
the other components and thus a regular exercise regimen is prescribed
for long, healthy lives.  Performing another study, using an
experimental format would not be feasible because of problems with
confounding variables, and doing so would introduce some ethical
concerns as they would be controlling behavior, forcing some people to
run, others not to. Perhaps additional study could be performed
measuring different types of vigorous activity, as alluded to in the
journal article.

Suggested Questions:

1.  What kind of study was this?  Observational?  Experimental?
Longitudinal?  What are possible advantages and disadvantages to this
type of study?

2.  What were the largest differences between the two groups, and how
did the study correct for these differences?