27 April 2013

Madness? Brain changes during ultramarathon endurance running

The most common question I get when I tell people I run mountain ultramarathons and that I am now  training for TDG is, not surprisingly, ”Are you crazy?” My short and rapid answer is, not surprisingly either, “No, of course not”.

Thinking about it more carefully though I think there is a certain amount of madness necessary for putting your body to such a strain as you do during both the actual race and all training before it. As Daniel Probst, a previous TDG finisher so eloquently put it ”For the Tor Des Geants you should have lost all signs of sanity. Your friends should be calling you crazy, you run 100 mile races back to back for fun and you enjoy the buzz of being awake for thirty or more hours at a time. You think walking for hours is just part of running, and you strike up conversations with imaginary creatures… If you get to the point where this describes you then you are ready for Tor des Geants.” I completely agree that you cannot overestimate the importance of mental preparations. But how should you do to prepare yourself mentally?

Coming back to the question regarding madness I read a very interesting article earlier this winter by Freund and colleagues in BMC Medicine 2012; 10: 170 regarding the effects of extreme running on grey matter brain volume. In this study, 10 participants of the 4487 km long ultramarathon TransEurope-FootRace 2009 were followed by magnetic resonance imaging (MRI) brain scans before, twice during, and about 8 months after the race. The average global grey matter brain volume decreased by 6% during the 2 months of racing and returned to normal after 8 months. This transient decrease is really large and should be compared with the normal age related decrease of about 0.1 to 0.2% annually or to the accelerated decrease in Alzheimer’s disease patients of about 2% annually. The decrease was not associated with brain lesions, nor could it be explained by edema. Possible explanations could be be loss of proteins, the runners also lost a lot of body weight, or hypercortisolism. The runners were all extremely well prepared for the race and had a training volume of 106.3 km per week (SD 35.3 km/week, range 50 km to 200 km/week) the year before the race.

The arrow points to a small periventricular lesion. The lesion shows no difference during the time course. However, the thickness of the subcutaneous fat layer (see red circle) shows a marked decrease from (A-C) and recovery at (D). (A) Timepoint 1 before the TransEurope-FootRace 2009 (TEFR09) in April 2009; (B) timepoint 2 during the race at 2,326 km; (C) timepoint 3 during the race at 4,005 km; (D) timepoint 4 at follow-up 8 months after the race. Picture from Freund et al. BMC Medicine 2012, 10:170

Albeit the small number of subjects in this “field experiment”, it is very interesting as it might give clues to the effect of extreme fatigue with energy deficits and could help refine research on the matter of mind over muscle into the mechanisms determining exercise tolerance. The next steps would be to further study whether the brain volume decrease is associated with functional reorganization of brain network activity and mental effects. The brains of the runners in this extreme race might have adapted to the demands of the race, in line with previous hypothesis discussed for instance in the paper by Paulus and colleagues in Neurosci Biobehav Rev. 2009; 33(7): 1080 a couple of years ago. As I have said before on this blog, in order to be good at running you should run, but expect that this will lead to a change not only of your muscles, but also brain.

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