Shortly
after I passed my fifth decade, I began to get membership solicitations in the
mail from AARP. They probably
do the same with everyone at that milestone. I guess they figured one needs a
lot of time to get ready for retirement. Anyway, after a good number of years
and countless similar pieces of mail, I’ve finally signed up. Though, I still
don't feel as I'm one of "them," yet. :)
At my age—and,
even many years younger--one too often hears talk about retirement, senior
citizen communities, long-term care insurance, complaints about various heath
issues, staying active and, at the same time, needing to slow down--altogether
rather depressing! What one doesn't hear much about is ... training.
This is
not to deny aging but to say that most people do not even get close to
exploring their natural physical limits. Not that long ago, I came across a
chart in an article that showed the physical potential of humans in
endurance activities vs. age. Unfortunately, I can’t find the article right now.
But, as I remember it, the physical potential increases to a maximum around
age 30 or so, followed by a gradual decrease with age. The latter decrease is
such that, not until one is well into the 60s does the potential drop down to that
of a teenager. Because most people don’t train, the actual fitness of those who
do train can be at the high end of the fitness of the overall population—though they may be targets of those AARP mailings.
The general lack of training is one example of what Daniel Leiberman at Harvard has termed, in his
book The
Story of the Human Body (See reviews 1, 2), "dysevolution" or "harmful form of change over time." Evolution here is not biological but cultural. Dysevolution leads to "mismatch diseases." These "mismatches are caused by stimuli that are too much, too little, or too new," relative to stimuli to which the body is adapted.
Lieberman’s
book presents a partial list of 49 hypothesized noninfectious mismatch diseases.
An example of “too little” (of vitamin C) is scurvy. An example of “too much”
(of starchy, sugary foods) is cavities. Scurvy is rare nowadays, because we easily
prevent its causes. Cavities have remained common, however, because we don’t address the
causes (fundamental dietary changes). Instead, we mitigate (e.g., brushing,
flossing) and adapt by treating the symptoms at the dentist office. There are
couple running-related mismatch diseases in Lieberman’s list, Athlete’s foot
and plantar fasciitis, that are also “too much” (of the modern, specifically,
running shoes). For more on barefoot vs. shod running, see this video of Irene Davis (Harvard Medical School and director of the Spaulding National Running Center) and related article, plus this great podcast from Freakonomics, “These Shoes Are Killing Me!” Contrast the modern, technology-laden shoes with this pair of 10,000-year
old sagebrush sandals (photo from the podcast).
On the
general lack of training, or just exercise, Lieberman recently published a fascinating article
on “Is Exercise Really Medicine? An Evolutionary Perspective.” Why people
generally don’t exercise, even though there are well-known and acknowledged benefits?
One key conclusion was that, while “physical activity is unquestionably a
potent medicine,
it never evolved for that role.” In addition, “chronic absence of moderate
physical activity was so rare until recently that, from an evolutionary
perspective, such levels of inactivity are not only abnormal but also cause pathology.”
Thus, “too little” (of exercise) represents a large category of mismatch
diseases. And, as is the case with cavities, we treat the symptoms of
inactivity. We know that exercise yields benefits at the cellular level (e.g.,
1, 2). And, we
also know the benefits, specifically, of running (e.g., 1, 2). But, from Lieberman’s evolutionary perspective, because we are just as adapted to
be physically inactive whenever possible (to conserve energy in an
energy-scarce world) as physically active endurance athletes (to hunt for
dinner—or, not become dinner!), just knowing the benefits of exercise is not,
obviously, sufficient. This second key conclusion led Lieberman to predict the
two most effective ways to increase the level of exercise in the general population: (1) making physical activity more enjoyable and (2) restructuring
environments to require more physical activity. But, those kinds of changes take time.
Meanwhile,
compression of morbidity (COM) might provide some incentive to get off the couch. “COM
means staying healthy as long as possible so that you decline in old age for as
short a time as possible. COM measures quality of life, not just quantity.” In a 21-year longitudinal study to test the COM hypothesis, runners lived an average of seven years longer than did the controls. More importantly, the runners' quality-of-independent-living age was, on average, 14 years younger. Of course, the
earlier one begins exercising, the better; but, it’s never too late …
Basically, (start to) run early (in life) and run often (thereafter). Our bodies need to be stressed, so they will adapt. The best medicine is
taking care of your body; the body will take care of you.
Running, thus, is almost literally my medicine in life.
