I am a 66-year-old soprano in our church choir, and I am noticing that my blood pressure skyrockets when I come home from practice, in particular after I have had to hit a few high notes. Tonight I was 150/102, and normally I am 130/80 or in that vicinity. Do you think this is dangerous, and what can I do about it? I have been home two hours, and it still has not gotten much lower.
This is definitely something to discuss with your physician. Only a doctor could say if it is dangerous. Often singing lowers blood pressure rather than increasing it so this needs to be treated wisely. Does your blood pressure shoot up from other physical exertion? If so, this might not be strictly related to singing.
The shift in blood pressure is likely related to the way you are breathing — possibly taking too large a breath and then having to work extra hard to make good vocal tone as a result. High notes require less air than low notes — more support but less air. They also require different resonance and perhaps reshaping the articulators can reduce the resistance of the voice and the impact on the body.
But again, I stress that you must discuss this with a physician. Once you know your blood pressure is stable you can work with a voice coach to refine the vocal technique and resolve the issue.