Friday, December 13, 2013

Hippocrates knew it. Galen knew it. EVERYBODY knows it! (So why are we still paying for research on it?)

It is totally fair to say that everybody knows that exercise is good for you, and overindulgence isn't.  Not all the details are known and they probably change over time and place, because there are various ways to exercise and various ways to eat, drink, and be merry.

But around 400 BC Hippocrates (whoever he/they was/were) clearly observed, knew, and stated that moderation in all things is good for health and longevity, and that exercise is part of that.  500 years later (yet still 2000 years ago), Galen was also very clear about the same points, and this from his own very extensive observation.  Yes!  "Evidence-based medicine" isn't new!

Hippocrates; Rubens engraving; Wikipedia

If we could give every individual the right amount of nourishment and exercise, not too little and not too much, we would have found the safest way to health. 
Eating alone will not keep a man well; he must also take exercise.                   -Hippocrates

And, Galen's view, as described by Jack Berryman in "Motion and rest: Galen on exercise and health" (The Lancet, vol 380:9838, pp 210-11):
Galen (c 129—210 AD), who borrowed much from Hippocrates, structured his medical “theory” upon the “naturals” (of, or with nature—physiology), the “non-naturals” (things not innate—health), and the “contra-naturals” (against nature—pathology). Central to Galen's theory was hygiene (named after the goddess of health Hygieia) and the uses and abuses of Galen's “six things non-natural”. Galen's theory was underpinned by six factors external to the body over which a person had some control: air and environment; food (diet) and drink; sleep and wake; motion (exercise) and rest; retention and evacuation; and passions of the mind (emotions). Galen proposed that these factors should be used in moderation since too much or too little would put the body in imbalance and lead to disease or illness.
Galen; Wikipedia
So, if we all already know this, and have known it for millennia, why are we as societies still paying for researchers to design even more studies so they could show this yet again, and again, and again, and...?  The latest instance is covered in a recent NY Times story reporting a study published in the British Medical Journal in October ("Comparative effectiveness of exercise and drug interventions on mortality outcomes: metaepidemiological study", Naci and Ioannidis, BMJ 2013:347).

The authors looked at studies of the effect of exercise on mortality from heart disease, chronic heart failure, stroke or diabetes and found that exercise was either as good as the standard drug treatment or better, except in the case of chronic heart failure.  The results show that exercise can be very effective, although medicine is the usual treatment prescribed (naturally).   
The results also underscore how infrequently exercise is considered or studied as a medical intervention, Dr. Ioannidis said. “Only 5 percent” of the available and relevant experiments in his new analysis involved exercise. “We need far more information” about how exercise compares, head to head, with drugs in the treatment of many conditions, he said, as well as what types and amounts of exercise confer the most benefit and whether there are side effects, such as injuries. Ideally, he said, pharmaceutical companies would set aside a tiny fraction of their profits for such studies.
But he is not optimistic that such funding will materialize, without widespread public pressure.
The bottom line is that we already know exercise is good for you, don't we?**  It is problematic that we yet need 'far more information', the usual researcher's plaint.  How many details do we need to know about, already knowing that they are largely ephemeral, when there are actual serious unanswered disease questions that we might study?  If half or more of diseases are in a sense treatable, preventable, or delayable with exercise rather than drugs, MRIs and CAT scans, surgery or other approaches, then why do we still allow doctors to meddle as much as they do?  Why do we still have to spend public funds, essentially to feed schools of public health, to keep on doing what are essentially retreads of the same old studies (with fancier and costlier statistical packages and other exciting technologies to make us seem wise and innovatively insightful)--when there are real, devastating disease problems with real unknowns that could be addressed more intensely? 

This is not to mention how much disease would be reduced if we had the societal guts to address poverty.  Real unsolved disease problems may be harder to design studies to understand, actually requiring new thinking rather than just designing some new sampling and questionnaires and the like.  But at least it would be a more real kind of 'research'.

One answer is that this is how the system, and what is basically its rote means of self-perpetuation works.  Science is a social phenomenon not just an objective one.  An institutionalized system doesn't insist on moving beyond essentially safe problems that we have a sufficient knowledge of, to face up to ones we don't yet understand.  That's riskier for professors needing salaries and publications, and administrators needing the overhead funding.  It's part of the fat in the system.

And fat, as we've known since Hippocrates, isn't good for you!

** Actually, despite this post, no, we don't really know this that quite as clearly as you might think!  We do certainly have lots of good mechanistic and physiological reasons why exercise is good, but some fraction of the association of exercise with health may be due to confounding: those who exercise are already healthier than average, or know or care more bout health, or they wouldn't do it (e.g., if they were too overweight, or had troublesome joints, etc.).  So those who exercise are not a random sample. Is it the exercise itself that does them good?   In any case, Galen thought so: he went to the gym regularly because he knew it was good for him!


Jari Stengard said...

Good blogging Ken.

I have always wondered, why we are willing to spend billions of dollars and euros to study gene variants that increase coronary heart disease by few per cent. when we already know that smoking, for intance, increase risk lot more than any of the "high" risk gene variants
And it is not expected that a knowledge of high risk carrier status would motivate individuals to change their life style (which is widely used argument to support gene studies) - people continue smokin gespite all (must) know that it is high risk behaviour.

As a public health person I do not need more information to tell my patients to eat healthy and excercise more. They are good (particularily if you enjou excercise and being outdoors) and -more importantly - usually they do not harm anybody unlike drugs - in order to prevent one heart diseease you may need (unnecessary) to treat 100 others (who may get side effects that all drugs have).

If we were rational, we should spend our money to studies that are designated to understand how we could get people to stop smoking (or more importantly -prevent young people to start smoking) and use drugs in secondary prevention (where they are known and shown to work well and where their use is better accepted, too).

Bot medicine and public health acts are social and cultural issues. We have plenty of things we can enjoy (i.e. easy access to food and no need to work hard to survive) and we are not willing to scrifice any of them. And most of us beliewe when scientists tell them that soon we are able to cure all disease (at least then when we know what our genes do). This leads a thinkking that we do not need to think risk behaviour -if we get sick medicine will cure it, or we can take a pill to compensate our high risk behaviour.

Ken Weiss said...

Absolutely correct. I would only add that there are clearly some diseases that are genetic in some reasonably tractable way, and for those some 'engineering' approach should be able to do what NIH et al. promise: cures or prevention based on genomic knowledge.

These can be devastating traits that exercise can't prevent or cure. That, rather than vague statistical causal effects, are what we should be investing much more of our research money in. And as far as epidemiologists are concerned, there are things they could be doing that would be more useful, such as making serious efforts at understanding the social aspects that you describe.

John R. Vokey said...

A propos of the more general concern with repeated epidemiological studies of causally-complex phenomena is this wonderful editorial by Ben Goldacre on the efficacy of bicycle helmets and mandatory helmet laws

John R. Vokey said...

Sorry, here is the link:

Ken Weiss said...

Another nice way to see how even the 'obvious' things are subtle, yet we need more 'research' always. In the case of helmets, the right thing to do is clearly unclear! One lesson is that my personal risk is not just about whether I wear a helmet but how it may affect my behavior and also whether other people are wearing them.

Anyway, enough idle chatter--I'm off to the gym.