science | nosleepingdogs

I’m a subscriber to New Scientist, the British weekly magazine of science news for the rest of us. I subscribed to Science for a while too, because it publishes researchers’ actual articles, but decided I’d rather have more numerous reports with less math. New Scientist contains short reports and a few longer articles as well as interviews, and a great feature at the end where people write in requesting explanations for odd observations (very British, I think, in the tradition of the journal Notes and Queries (1849 – present), or letters to the London Times from country parsons reporting the first sighting of a bird).

Anyway, though I still find NS interesting and valuable, I’ve begun to feel they are sometimes sacrificing science for snappy headlines. Here’s an example that is from a while ago, but quite illustrative.

Housework helps combat anxiety and depression

FEELING down? You might be able to dust away your distress. Just 20 minutes a week with the vacuum cleaner or mop is enough to help banish those blues, and sport works even better.
That’s the message from Mark Hamer and his colleagues at University College London, who wanted to find out what benefits arise from different types of physical activity. They examined data from questionnaires filled in by almost 20,000 Scottish people as part of the Scottish Health Surveys, carried out every few years. Some 3200 respondents reported suffering from anxiety or depression, but those who regularly wielded the mop or the tennis racket were least likely to suffer, the researchers report (British Journal of Sports Medicine, DOI: 10.1136/bjsm.2008.046243).

One 20-minute session of housework or walking reduced the risk of depression by up to 20 per cent. A sporting session worked better, reducing risk by a third or more. Failing housework or sport, says Hamer, try to find something physical to do. “Something – even for just 20 minutes a week – is better than nothing.”

––From issue 2652 of New Scientist magazine, 19 April 2008, page 4-5. Abstract of original available free, entire article requires fee to BJSM.

Why we shouldn’t believe this

In New Scientist’s brief bit, there’s absolutely no evidence for a causal relationship between exercising and being less depressed. It’s an example of the frequent, but quite false, assumption that because two things are associated, one causes the other. Other relationships are quite possible. Does physical activity really reduce depression and anxiety, or are the people who actually do housework or sports simply the ones who have less severe symptoms to start with? Or is there some other connexion altogether? Nothing in the New Scientist, or the article abstract, addresses that question. But it makes an eye-catching headline, to say that housework cures depression.

To investigate the question scientifically, it is necessary to take a large number of depressed people and randomly assign them to one of three groups: an exercise group, a control group given some other task like filling in a weekly questionnaire or reading about depression, and a third group who don’t get any new activity or other attention from the researchers. (Ideally those doing the testing and analysis don’t know which group is which.) Then, at the beginning and end of the study, measure psychological state using some accepted reliable tests and see what changes. Finally, use statistical analysis to see if the changes are significant or might be due to chance. [Even after that, other factors may make the apparent conclusions false: maybe the exercise was not enough to have an effect, or during the study the country went to war and everybody stayed depressed, or the social aspects of being in an exercise group had more effect than the actual jumping and sweating did.]

No doubt such a study has been done, probably more than once; advising depressed people to get more exercise is a standard approach and insurance companies would love to fund the research to support it. Mark Hamer might have cited previous work in the full text of his article in the British Journal of Sports Medicine (which New Scientist should have read before writing their brief and provocative piece) but we readers have no way of knowing this.

In this particular case––the effect of exercise on individuals––researchers would have to be vigilant about the distortion of results due to participants dropping out or failing to comply with the activity levels. Even the method of choosing participants can affect reliability of results: if the depressed people are chosen from those who show up at clinics, their symptoms may be overall less severe than the symptoms of people too depressed even to go to a clinic.

A similar example: exercise and fibromyalgia

I have fibromyalgia, and some researchers have pronounced aerobic exercise to be beneficial for reducing the symptoms of this condition’s chronic pain and fatigue. Exercise is fundamentally a good thing, I agree. It distracts one from symptoms, adds an interest, may confer a feeling of control over one’s illness, strengthens muscles, promotes growth of new neurons in the brain, and can improve flexibility.

But. In moderate to severe cases of fibromyalgia, even mild exertion can cause greatly increased pain and exhaustion. Unlike the familiar “weekend athlete” reaction, the increased pain and fatigue may last a week or several weeks. This means that for some individuals the goal of walking briskly for a few blocks could take years to attain, since we are knocked back to the starting point when we overdo, or when something else in our lives like a cold or interrupted sleep aggravates our symptoms.

Some time ago I read a review article which gathered the results of a number of studies on exercise and fibromyalgia, and I noted that in some the dropout rate was high but wasn’t mentioned in interpreting the data. And then there are people, like myself, who would never enroll in an aerobic exercise program because we’ve “been there, done that” and it was painful and unproductive. If we’re not counted, and a high dropout rate is glossed over, then to whom do the results apply?

What can we say about exercise, then?

I am skeptical of the efficacy of exercise as a general one-size-fits-all prescription for fibromyalgia or depression. I would suggest the fibromyalgia studies really show that exercise appears to be helpful for those people able to endure it, but, while all patients should be encouraged to do appropriate activities as tolerated, there’s a need to be gradual and cautious. Some patients may never be able to attain exercise levels that make appreciable improvements to their symptoms, despite sincere efforts. (This doesn’t mean that exercise is without benefits to them, though. My level of physical activity doesn’t seem to help my pain, fatigue, or quality of sleep, but I’m much happier when I get out for a walk or a bit of gardening.) At an education class on fibromyalgia, I heard someone ask “How can I exercise when even walking around the house is too strenuous?” The reply was, “Can you get up and walk all the way around your kitchen table? Good. Start with that and work up.” Sensible advice, but actual improvement in symptoms may be a very long time in coming for that person.

For depressed people, exercise is unlikely to be harmful and may indeed help––I myself believe that it does––but there’s no evidence of that in the New Scientist account of Mark Hamer’s work.

I felt this was worth writing about for two reasons, one general and one particular. It’s a good example of how the media gives us accounts of scientific research without the details needed to evaluate them. And, invisible conditions like fibromyalgia and depression are different from most other health problems. They are regarded by many as non-ailments or personal weakness/malingering, so it is easy for “exercise may help” to become “quit complaining, pull up your socks and get on with it”. From there it’s a short step to “all these patients could feel better but they just won’t do the work necessary; they cling to their disease.”

And I have to admit that the example used, housework, was particularly galling to me. While there are people who can enjoy housework as a zen activity, or feel great satisfaction at making their floors and sinks shine, most of us (male or female) do not get much pleasure at all from it. Every time you do it, next day there it is again, dirty dishes, laundry piling up, dog hair floating across the floor. Truly, housework is never done. And, given that housework is still seen more as a woman’s responsibility than a man’s, and that women have a higher rate of depression than men, the “FEELING down? You might be able to dust away your distress” line seems offensively sexist and dismissive.

Book cover image from Amazon.

Nano, the emerging science of nanotechnology. Ed Regis.

I picked this book up at our Friends of the Library bookstore for a quarter, though when I saw the publication date of 1995 I had second thoughts. How could so old a book, on such a fast-moving aspect of technology, be worth reading?

But when I started it I was immediately drawn in, and after finishing it conclude that for us non-scientists, as well as for those interested in the background and implications of the whole “nano” idea, the book is well worthwhile. The focus is on Eric Drexler, who as an MIT engineering undergrad in 1976 formulated the basic idea of assembling substances or structures one molecule or atom at a time, and became what Apple used to call an evangelist for the idea for the succeeding decades.

Drexler was not the first to discuss the possibility of such constructions––that honor goes to the ingenious mind of Richard Feynman who broached the topic in a 1959 lecture––but he expanded upon it, foresaw not only multiple uses but also some of the social/economic consequences of a technology which could lead to all of us having tabletop “matter assemblers” which could produce anything, from a ribeye steak to car parts, using just about any old “stuff” as raw material. And Drexler organized others into a bi-coastal league of nano-fans to brainstorm, research, and support the vision. At least, he did that after the first few years when anxiety about the social impact, or the possibility of runaway assemblers covering the earth with “grey goo,” led him to keep the idea more or less under wraps.

Ed Regis is an experienced science writer of the sort that used to be dismissed as “popularizers,” because they write for the general reader, one who’s interested, educated, but not schooled in the particular branch of science under discussion. He writes for publications like the NY Times, Wired, and Scientific American, as well as writing books. He’s good at what he does.

This book, for example, explains Brownian motion (the jumping about that individual particles, from atoms to pollen grains, do when suspended in liquid) and the workings of scanning tunnelling microscopes (which proved able to manipulate individual atoms), and other such things, well enough that I was able to explain them to someone else. That doesn’t mean I have any real inkling of the physics or mathematics of it all but I have a degree of layman’s understanding which enables me to follow the discussion, and I can build on it if I wish to read more.

Brownian motion was early raised as a theoretical objection to the concept of moving atoms around to construct molecules: how could you do it if your atoms wouldn’t stay put? An early response was, “If our own cells can make molecules, then it can be done.” A later response was the demonstration that it had been done; researchers pushed atoms around to make letters and pictures. Since then, other researchers have used enzymes or gene-altered microorganisms to tailor-make specific molecules.

Regis includes a lot of what could be disparaged as unscientific human interest detail–personalities, anecdotes–but to me this added more than just readability, it added another dimension. The original concerns about the human future which motivated Drexler to think about fundamental technological change, the ability of a high school student to make his own scanning tunneling electron microscope, the accounts of scientific rivalries and misunderstandings, these have a place in a popular account of a technology that is so mind-boggling and promises or threatens such far-reaching upheavals in society.

As I finished, the question in my mind was “Why haven’t I heard more about huge strides in this technology in the years since the book’s publication in 1995?” I’m looking into that question now, with much more comprehension than I had before reading Regis’s book.