If you have obstructive sleep apnea and you take arbs for persistently elevated blood pressure, does this increase or decrease oxygenation during hypoxic apnea? isn't the hypertension a healthy adaptive response?

Hypertension is often a byproduct of sleep apnea, but it is certainly not a healthy response. And untreated high blood pressure as a result of sleep apnea contributes to the stroke, heart failure, and heart attack that we see in this condition. Take your blood pressure medications. And treat the root of the issue, which is the obstructive apnea.

You appear to be confused about your medical situation, and need to see a pulmonary specialist or sleep specialist and get the sleep apnea under control with a C-PAP unit. If you already have high blood pressure, the ARB category is a good choice, but these drugs do NOT affect oxygenation. Visit your doctor and have a full discussion regarding appropriate management.