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!

The genomics of potatoes: couch potatoes!

Here is the latest on your tax money at work.  A study, as intellectually deep as the cushion in your TV room, published in the special physical activity issue of The Lancet that precedes the Olympics, shows the stunning fact that idleness is as dangerous to your health as smoking.  It's not just that every idle person, like every smoker, actually dies (though perhaps in a blissful state in at least the former case) but that the risk of death from diabetes, heart disease and even some cancers is comparable to the excess risk of smoking.  Say the authors,

Strong evidence shows that physical inactivity increases the risk of many adverse health conditions, including major non-communicable diseases such as coronary heart disease, type 2 diabetes, and breast and colon cancers, and shortens life expectancy. Because much of the world's population is inactive, this link presents a major public health issue. We aimed to quantify the effect of physical inactivity on these major non-communicable diseases by estimating how much disease could be averted if inactive people were to become active and to estimate gain in life expectancy at the population level.

We're not minimizing the nature of the finding, because results from many studies over many years make it no surprise whatever that exercise is good for your health.  The cure is not to have more and more expensive studies, but....well, to just get off your duff!

Of course, the Pharmas that want you on lifetime meds will argue, perhaps not explicitly, that 'today's lifestyle' puts people at risk of X disease for which they have the preventive pill.

If this is, as the lead author of the paper dramatically says, a pandemic (at least in Britain where the study was done), then we have the makings of the next round of Big GWAS studies.  Another paper in The Lancet addresses ecological factors that might explain why some people are active and some are not, but surely there will soon be a demand by the general public (of epidemiologists and geneticists) to know the genetics of who is is exactly that is vulnerable to this disease (which is likely soon to be named, say, as indolitis, and added to the official list of diseases, thus making it a disease).

For some, we'll surely hear, watching endless sports and mindless programs will do no damage to life expectancy (other than making you brain-dead at a very young age).  We need, absolutely, to know their genotypes and once we do, if they show their genotype diagnosis from 23andMe they'll be allowed to buy a huge-screen TV.  Without a clean bill of genetics, they'll be denied access to Best Buy.   Or, perhaps new TV's will have a slot for you to put in a credit-card size genotype record before you can turn it on, much like some cars have breathalyzer screening before you can start the engine.

Now, we already do know a lot of the genotypes, but until now we didn't know why.  Those are the countless genes associated in existing GWAS studies with diabetes, cancer, heart disease and so on.  We thought this had something to do with the gene networks involved in glucose metabolism or detection of aberrant cell muations that might lead to cancer.  But instead, these genotypes will now have to be studied to see how they interact with sofa postures, and perhaps channel choices (will those who watch sports be at even higher risk than average for an indolitis victim, or will that be somehow protective because sudden-death overtimes stimulate adrenaline release?).

Other potato-consequences you might not realize!
You not might think about it right away, but indolitis actually reduces the risk of many different diseases.  Most cancers, many types of senile dementia, and a host of other diseases will decrease in frequency.  In that sense, being a couch potato protects you against those, while excercise protects you against the diseases mentioned in the Lancet article.  That's because indolence will lead to those latter traits, thus preventing you from dying of the others.  It may be true that those would have got you at a later age, but, hell, we all have to go sometime, so it's your choice of how and when. If you have indolitis, you at least have some information....almost as precise as if it came from a genome company.

Good for business, too
Soon, an epidemiologist from a university near you will be asking for a blood sample and an exact reckoning of your TV-watching habits.  Please cooperate, as this is going to be the mother of all epidemiological studies.

And of course this will be good for anthropology, too (we're happy to say!) because it will allow some of us quickly to get in touch with the NY Times (or Nature or Science) to explain how it may seem that we evolved to be active and hence healthy, but perhaps others will argue that we evolved to sit around the campfire gossiping rather than wasting energy chasing wildebeests or berries too high on the bush to reach.  Whatever our story, we'll surely be searching for evidence of natural selection in the genes that are implicated in indolitis, so we can explain why they're here.

Good for one and all!  So sit back and relax until the stories start appearing....

Another miracle cure -- the 3-minute-a-week exercise plan

Alas, another story that starts with "The Truth About...".  Why do these stories all seem to promote miracle cures?  Last week sugar was toxic, and now, exercise makes you fat, but there's a cure!  Maybe if you quit going to the gym, you can go back to eating sugar.  Though, the obvious next finding is that what's killing you is not just sugar, or exercise, but the sugar you eat because your exercise makes you hungry.

What's the story?  It turns out that three minutes of high intensity exercise (HIT -- High-Intensity interval Training) will make you fit.

The HIT approach, combined with gentler exercise such as walking and even fidgeting (yes, there’s an acronym for it and it’s NEAT – Non Exercise Activity Thermogenesis), will do the trick.

Walter Mosley at work -- briefly

Yep, much better than 3 hours a week, because those three hours make you hungry, and worse, give you visceral fat, which is the kind that kills you.  A BBC presenter, Michael Mosley, was put through the paces -- or rther, lack of paces -- at Nottingham University, where investigation into the effects of HIT vs traditional exercise are underway.

Scientists at Nottingham University who measured Mosley’s reaction to the High-Intensity Interval training (HIT) sessions recorded a 30 per cent improvement in the effectiveness of his insulin action: that’s the body’s ability to move glucose out of the bloodstream — where it can become a toxin and lead to the build-up of dangerous visceral fat — and into muscle tissue, where it is of benefit.

Just for the record, this sounds suspiciously like what cutting sugar out of your diet is supposed to do for you, as well. And you don't have to have a gym membership for that!

Who knows?  Maybe these guys are onto something.  But, this 'everything in moderation' taken to the extreme seems .... a little extreme.  The paper on this work hasn't yet been published (but will be soon), but it does seem as though whether this method works for you depends on what you exercise for, and thus how you measure it.  And, if you're exercising to lose weight, clearly it shouldn't be the only thing you do, so the idea that exercise alone will help is iffy; if you're exercising because it's how you meditate, or you really love doing it, 3 minutes a week isn't going to do it.

Ken was in the Air Force a while back (a long while back), and they had adopted an exercise/fitness program developed by the Canadian Air Force.   It was called 5BX, and was only a few minutes a day, but at a graded intensity level.  If you progressed through that you really were fit, at least for some short-term exercises.  But that was before the aerobics era, in which you had to do exercise for enough time to shift your energy use from short-term to stored (anaerobic to aerobic), and the point was to get your heart in shape.

Since then the jogging fad or habit spread widely, again led by various gurus and their claimed magical ideas.  Lot's of us run, bike, swim, or whatever, and while some of the gurus have died of coronaries while running or whatever it is they do, overall it seems to be quite salubrious.  But, what it's good for depends on what you're doing it for.

Pull up or pull out?

Well, here's another stunner. After all this time, we still don't know what amount or what kind of exercise is best. With all the money, marketeering, and other scientific interest involved in understanding what makes us sick, what we know is that some exercise is good for you...but not too much. And older people don't like vigorous exercise.

How could it be that after billions of dollars in research (and promotion) over many decades, we don't know? After all, you can find routine comments about the virtue of exercise in, say, Victorian novels (and, though we haven't looked, probably in Hippocrates 2500 years ago).

This reflects the serious if not fundamental problem with epidemiology, a problem at least as serious as making causal inference in genetics, where at least DNA segments can be objectively identified. In our posts last week on reductionism, we discussed the way that science 'tunnels' through complex reality by reducing studies to isolated variables to identify their causal effects on some measured outcome. We noted that in genetics this has provided a phenomenally successful way to discover many things that genes do. But it leaves the genetic contribution to most interesting traits, known by a catchword as 'complex', poorly accounted for in any specific way.

In environmental and lifestyle epidemiology, that deals with the common causes of disease and death in the industrial world, even tunneling (with all its limitations) is exceedingly problematic. That's at least in part due to the fact that exposure variables, unlike genetic sequences, are poorly defined and measured. 'Exercise' or 'diet' are examples, but so are many other aspects of modern life. This is especially true when the fact as well as the amount and duration of exposure are needed. Who can remember what they did, or ate, decades ago--all the way, perhaps, back to early childhood? At least, we're exposed to our genes from conception, and infectious diseases often are clear-cut point-causes where a single exposure can do the trick: one sneeze from someone with the flu is enough.

Besides the fact that it's hard to isolate individual variables, such as diet or exercise, in a cogent experiment, the variables of interest are heavily confounded, that is, diet is correlated with many other aspects of our lives, measured (e.g., education, income) and unmeasured. The same is true in genetics (e.g., what's called 'linkage disequilibrium' or 'epistasis', for those who know genetics), but easier to at least think about if not measure (though by no means trivial). But if eating chocolate rather than, say Supersize sodas, is correlated with exercise, and because these are both correlated with social status, jobs, education, neighborhood, race, and so on, then it is nearly impossible to isolate one of those variables. Confounding is a very serious, if not lethal, problem for application of 'tunneling' approaches in epidemiology, even if they would work. But because of complex causation, it probably wouldn't.

We've previously posted about the problem that preventive screening as in mammography to detect breast cancer may over-diagnose and over-treat lesions that would go away on their own or turn out not to be cancer after all. Studies showed that those not screened had fewer deaths from cancer than those who were screened. This has both monetary and psychological costs. It challenges various vested interests, too, so it's not surprising that we need yet another study (with its costs, too). So the latest U-turn in this saga is getting headlines, threatening policy changes (or no-changes), because it defends screening. And a BBC report interviewed a Scandinavian expert who bluntly ridiculed the current study as patently wrong. We can't judge without attempting to read the latest studies, and their skeptics, which we haven't done. The statistics are subtle and one can probably find in them what one wants to find. But the point here is the problem of uncertainty, even in heavily studied issues, is what concerns us here.

There's no easy answer, but the fact that there's a problem is clear. Candid epidemiologists who recognize this (privately, of course, because doing so publicly will jeopardize their funding changes, as we have been told many times) often turn in frustration to genetics. They believe that we have The Truth because genes, being molecules and the blueprint for life, have to be more tractable. Well, sorry, but it's not so simple on the genetic side of the fence either.

Dealing with complexity is a challenge. Somehow, the latest finding still makes it into the news, even though we really know that next week or next year the reverse will be announced. When and how we'll start making better progress is anyone's guess.

Meanwhile, do your pull ups, but don't pull out of your health club membership.