Exercise matters. Not only in general, but specifically when it comes to the brain.
The underlying mechanism(s) through which exercise keeps the brain in shape remain elusive. In a prior blog post I listed a number of possible explanatory scenarios of how and why exercise might work.
One of the possibilities I discussed was that exercise might decrease the risk for Alzheimer's dementia. This known protective effect is usually thought of as a indirect benefit of the overall improved general state of health and stamina that comes with any regular physical exercise routine. But is this the whole story?
In a new study from Washington University researchers found that exercise seems to decrease the presence in the brain of the (in)famous amyloid beta, a high-profile protein in the Alzheimer's story.
What seems to be happening is that some genes (the ApoE-ε4 famiglia) get too greedy for that sticky amyloid, and as a result it messes up the brain; one can turn up the exercise volume and voila: the brain's act gets cleaned up.
Of note, exercise seems to take matters into its own hands only when there is too much amyloid hanging around for no good reason. In other words, if you are an amyloid hoarder, you'd better start exercising. And that will reduce your amyloid deposits. However if you don't have that much amyloid to start with, exercise will not make a big difference. The take-home point: Exercise seems to be a great amyloid equalizer (for a more detailed discussion click here).
Of course, you will now want to know how to check those amyloid levels or your ApoE-ε4 status. At this time, the only way to check amyloid levels is via a spinal tap or a special type of brain imaging called PET. You are looking at research procedures really, as none of this is done routinely in a doctor's office. ApoE-ε4 is also not available as a routine test.
That's the bad news.
The good news?
I would like argue that this lack of knowledge might be for the better. Ignorant of the your ApoE-ε4 and amyloid make-up details, you now know that you have little to lose and a lot to gain if you take up exercise.
It's good to get rid of the amyloid (but only when there is too much of it lingering around), meaning keeping not only your body but also your brain in shape.
References:
Head D, Bugg JM, Goate AM, Fagan AM, Mintun MA, Benzinger T, Holtzman DM, Morris JC. Exercise Engagement as a Moderator of the Effects of APOE Genotype on Amyloid Deposition. Arch Neurol. 2012 Jan 9. [Epub ahead of print]
© Copyright Adrian Preda, M.D.
