From the abstract, it looks like they just gave the participants a survey, and did an MRI. Actual time spent with the participants probably wasn't more than a few hours for just that (probably for cost reasons too).
Sedentary behavior inhibits quality sleep, which has been shown to impact memory.
I wonder if researchers tracked the quantity and quality of sleep (REM vs NREM) among study participants. From the graphs it doesn't look like they did.
Perhaps a sedentary person makes fewer notable memories (their surroundings don't change much), and the respective area of the brain atrophies?
" No significant correlations were observed between physical activity levels and MTL thickness. Though preliminary, our results suggest that more sedentary non-demented individuals have less MTL thickness. "
So, this wasn't conclusive? Just in case i may walk my dog twice as much but not much can be done with a software engineering job and sedentary hobbies.
Interesting that you bring this up. I don't know the answer, but I'll be 29 this year and have just recently started getting some gray hairs. The most prominent are two gray patches right over my temples.
Yes, it may be just a coincidence that this is so, with the temples and the temporal lobes being physically close to one another. But intuition makes me wonder.
Biologically, this doesn't make sense. One of the more accepted causes of graying-1 is a build of of H202 in the hair follicle resulting in the hair not holding as much melanin. It seems unlikely that this would come from the brain, through the skull since that's not how the circulatory system gets in/out of the brain (it mostly goes through the neck/spine).
Indeed, but if control and resources (e.g. immune resources) are allocated via some kind of map in the brain then mightn't that make proximity relevant? (notwithstanding the bone barrier!) I admit it's a stretch...
Again, not really how things work. You're assuming that the dermal layers closest to a section of the brain are somehow working with that section of the brain and that's not really how it works. The circulatory system (which is most likely what's responsible other than the skin/dermis itself) doesn't route from brain to skin that way (because of the bone).
There is a pretty large concentration of veins/arteries - 1 that come up around the temple, so that could be related to the frequency of graying starting there.
anecdotally, i have been fairly active (5+ mile daily bike commutes, weekend hiking, snowboarding, ect) in my 20s and started going gray around 27.
Somewhat crazy idea but anyone know if sedentary behaviour or poor memory are associated with graying hair at the temples?
"Indeed, one can be highly active yet still be sedentary for most of the day. "
That's a hugely interesting note there in the introduction.