Stephanie Kolban said:Interesting hypothesis regarding the fall equinox. Why,
however, would it be more pronounced while living in Fl
rather than Ma? It seems to me that the more temperate Fl
climate would lessen the seasonal effect. Or, did I
misunderstand your hypothesis?
Hi Steph,
It has to do with relative sun intensity, much like the
relative BG sensor in the brain for hypoglycemic events. We
have to reset the BG sensor when we become hypoglycemic
unaware. A similar process happens with bright sunshine when
living long-term in Florida (IMO). So we need to reset the
sun sensor from the eyes to pineal gland with bright light.
This synchronizes the body with yearly hormonal cycles that
slow the metabolism in the winter months and increase the
metabolism in the summer months. This is the major cause of
yearly HbA1c cycles, IMO. But this HbA1c link has yet to be
proven, so this is my hypothesis.
My personal HbA1c data shows a 0.3% yearly variation in
Florida versus a .7% variation in Boston (for constant red
blood cell cohort weighted glycemia over 120 day mean
lifespan with 10 day standard deviation). This variation is
what I see theoretically if BG is identical in both
locations when trying to achieve my 6% HbA1c target. My
personal data suggests that if I lived at the equator, I'd
have less yearly variation in HbA1c. But I need more years
of data to make sure this is true for me.
My hypothesis about low cortisol synchronized and delayed to
the fall equinox also needs more data. So I'm waiting to see
if I have higher insulin sensitivity this October, that in
turn causes nocturnal hypoglycemia. This past October, I was
clobbered 3 nights (4 in 7 days) in a row even after
lowering my bedtime NPH. So my "apparent" dawn phenomenon
was much lower for roughly a week, even though it is not
supposed to be caused by cortisol. But obviously, if
cortisol is low, insulin requirements drop as well. This
will appear as a weaker dawn phenomenon. (I clearly could
not be sick at this time, as that would increase my insulin
requirements.)
In any case, if the sunlight is brighter, the pineal gland
should have a stronger impact on hormonal cycles. This would
suggest an increase in cortisol after the spring equinox for
higher activity levels in the summer; and, a decrease in
cortisol (exercise stress hormone) after the fall equinox in
preparation for lower activity levels in the winter. The
change in this stress hormone could cause a temporary
disturbance in BG management. (The pineal gland kicked the
cortisol "daily pacemaker" and it took a few days to get
back on track.)
That's the theory,
--
Jim Dumas T1 4/86, background retinopathy, rarely
hypoglycemic: <1/mo. lispro+R+U+NPH daily, moderate
exercise, typically <6% HbA1c