Interesting information here, thanks to everyone who’s contributing.
dwc1970, a hefty sneeze will raise your blood pressure momentarily. The dizziness you feel is akin to that you get if you stand up too quickly. I think.
Back to hyperventilating. Does the term refer to quick breathing or quick, shallow breathing? One problem with shallow breathing is that you may not be expelling all the dead air in your airways, resulting in little fresh air getting to your lungs, resulting in higher CO2 and lower O2 concentrations in the air in your lungs. Is that a factor in hyperventilation and its effects?