This is a reposting of one of my original post on Sharpbrains. I posted "The Brain Virtues of Physical Exercise" in August 2008. I just reviewed it today and I found a number of interesting comments that I will discuss on this blog.
So, for a starter, here is the original post. I will follow up with a series of posts discussing the some of the interesting points raised by my commentators.
Brain Lessons Part 1
Let me start with a list of common biases: expensive is better than cheap, free is of dubious value (why would then be free?), rare is likely to be valuable, and while new is better than old, ancient is always best. Which explains a common scenario that is reenacted about twice a week in my office. It starts like this: a patient shows me a fancy looking bottle of the brain supplement of the week: ancient roots with obscure names mixed together in another novel combination which you can exclusively find in that one and only store (rarity oblige!). And not to forget: it ain’t cheap either! Of course, there it is, the perfect the recipe for success: ancient yet new, rare and expensive. It got to be good! But is it, really?
The problem with recommending physical exercise when it comes to brain fitness is that is doesn’t have any of the glamour traits I have just mentioned: it’s been around for a long time – so there is nothing new and exciting about it, there is no fancy name or exclusive label marketing it and, worst of all, it is as cheap as cheap can be: not only free but also available in unlimited supplies.
So when I tell my patients that the single most important thing they need to pay attention to when it comes to keeping their brain in shape is exercise, I invariably get a “really, and you needed to get an MD to tell me this?” look. Nowadays everybody seems to know that physical exercise is good for the brain. Big news they say. And they needed to study that? Duh?
For most it’s no big surprise to find out the people who have a physically active life style have a decreased risk of Alzheimer’s dementia or the number of blocks one walks everyday appears to inversely correlate with the rate of cognitive decline later in life. It sort of makes sense to assume that has to be the case. Here are a few well established facts.
First of all, regular physical exercise correlates with improved health – meaning less risk for high blood pressure, metabolic problems (cholesterol, lipids and glucose dysregulation) and weight gain, which is all good for the brain. A healthy brain needs a healthy environment, doesn’t it? Or to put it in a slightly different way: an unhealthy environment would not be good for the brain, wouldn’t it? I think we would all agree on that one.
Now, would a healthy environment not only protect but also improve the brain structure and performance? Would it also promote the growth (if possible) of the brain? The answers to such questions are less obvious. For example we know that not all healthy people end up with “good brains”. Well, why is that? Specifically, when it comes to physical exercise then, are there such things as a minimal dose of exercise that can result in positive brain effects? And is there a maximal or “toxic” dose of physical exercise, which may in fact hurt the brain? Is all physical exercise equally good for the brain or do different physical exercise routines differ in terms of their brain effects? I put those questions on the table and the chance is that I got the “duh” people’s attention.
First, let me say that to scientists the physical exercise question is no different that any other scientific question. Scientists tend to be a skeptical bunch and as such they like to always point out that correlation does not necessarily imply causation. Take the old active people who didn’t get Alzheimer’s example. One possibility is that their consistent exercising keeps them from getting Alzheimer’s. But what is it that got them to exercise more in the first place? Could it be that their brains were equipped with the sort of gear that gets one excited about pushing oneselve a bit, which would then result in these fellows being more prone towards doing physical things to start with? Then they will be more active physically but that is because their brains were wired differently from the gecko and that, in itself, might have decreased the risk of Alzheimer’s dementia. In a situation like this physical exercise is what scentists call a confounder – i.e. a concomitant but not necessarily casual event that can falsely be seen as a cause resulting in the final effect.
How can one figure this one out? Over the next few columns we will look together at ways of answering apparently not so straightforward questions about physical exercise and the brain.
Now, to begin I will like to make this column, to whatever extent possible, an interactive forum. And that is as it turns out that the brain really likes it when it’s asked to be “active”. Passive audiences, which are spoon fed information, score less well when tested on retention and understanding of the presented material than audiences that were kept engaged through the process. So, in the spirit of “engagement” I will start by asking a few questions about what is important when it comes to the effects of physical exercise on the brain. Depending on what your answers will be we will then take it to the next level, i.e. critically examine the research evidence about specific brain effects of different types of physical exercise.
So, consider which of the following possibilities will get you convinced that physical exercise is good for the brain. Would you be convinced if exercise has been shown to:
1. Increase longevity (as a better brain should make us live longer, shouldn’t it)?
2. Decrease the risk of Alzheimer and other types of dementia?
3. Decrease the risk of “normal” age related memory loss or cognitive decline?
4. Increase one’s ability to problem solve?
5. Decrease one’s risk for depression or anxiety?
6. Improve one’s memory, concentration and attention?
7. Improve one’s ability to feel consistently happy?
8. Increase the number of nerve cells or nerve cells connections in the brain?
9. Correlate with higher education?
10. Correlate with higher social economic status?
11. Chemicals released during exercise were shown to pro¬mote nerve cell growth?
12. Exercise would “correct” chemical abnormalities reported in mental or brain illness?
I am looking forward to your answers. Please do not hesitate to come up with other questions or hypotheses. We’ll make this into an exercise about how to think about physical execise. Another form of exercise that might be good for the brain.
© Copyright Adrian Preda, M.D.
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