I'm noticing what may be a connection between CPAP use and blood sugar elevation and am curious if anybody else has observed or wondered about something like that also.
My morning blood sugar levels are significantly lower when I don't use CPAP. And I'm even wondering if CPAP use could have been a major factor in my recent development of type II diabetes.
I've been on CPAP (UARS & mild OSA) for 1.5 years. APAP, with pressure set 4-8. Use Aura nasal interface that seals very well.
Two years ago, my fasting blood sugar was a non-diabetic 90. In November 2006, however, I had a fasting level of 162, considerably into the type II diabetes range. My doctor commented that was quite a large increase for 2 years (my weight had not increased).
Since then, with diabetes medication (metformin), etc, the morning reading has dropped to 120 (should be no more than 112).
However a couple weeks ago I happened to mention my concern about morning blood sugar and also being on CPAP to my chiropractor. He immediately and emphatically declared that CPAP could be raising my blood sugar by cutting short my exhalations, thus creating a breathing pattern that is consistent a 'fight or flight' anxiety state, with the subsequent increased adrenaline (and/or cortisol?) causing my liver (or muscles?) to release more glucose into my bloodstream.
Now that was exactly what I'd been suspecting, having read that elevations in cortisol and/or adrenaline (or other stress-related hormones) could raise blood sugar overnight. And I'd also long been concerned about the 'panting' effect of the cut-short exhalation.
With that endorsement of my thinking, I tried a few nights without CPAP. Results: My morning blood sugar levels were about 20 points lower each morning, about 100, a very significant drop! Then I went back to CPAP for two nights, and it shot up 10 points. Then slept last half of last night without CPAP and this morning got my lowest blood sugar reading yet, 89!
My primary care physician had agreed with me, when I first went on CPAP, that the disruption of the usual relaxation breathing cycle in which exhalations are roughly twice as long as inhalations could exacerbate anxiety.
I should note that both my PCP and chiropractor are yoga devotees. And I have long used slow breathing with long exhalations to control my anxiety problems. So all three of us are at least somewhat oriented to view inhalation/exhalation ratios of important.
Perhaps those not as anxiety-prone as I am might fare better. And, of course, it could be something other than inhalation/exhalation ratios about sleeping with CPAP that is causing the discrepancies.
My sleep doctor, a neurologist, pooh-poohed my concerns about I/E ratios when I mentioned it to him 1.5 years ago (haven't spoken with him since and planning to find a new sleep doctor). Yet I've read that respiratory therapists set respirators to I/E ratios of around 1:2.
Even awake, trying to extend my exhalations while hooked up to CPAP at just a pressure of 4, I find it difficult make my exhalations longer than inhalations: That pressure just doesn't allow that. (CFLEX seems to hurry my breathing even more, so I have that feature turned off.)
Any comments on this?