Disclaimer: There is an article in the British Journal of Medicine that looks at the causes of an earlier mortality in sax players than in other jazz musicians. Their conclusion is it must be circular breathing effects on the lung that causes their premature death ad they are the only instrumentalists using this technique.
This reasoning is flawed as they are NOT the only instrumentalists using this technique. Perhaps the only instrumentalists using this technique when freebasing cocaine, but NOT when breathing normal air.
I also did an experiment when I was hospitalized in the intensive care unit last year with tubes stuck into every orifice in my body (and a few created ones) while hooked up to monitors. I had my trumpet with me a practiced daily in my hospital bed while attached to these medical instruments. I did circular breathing experiments and found this interesting observation. My blood pressure stayed stable. My pulse stayed stable. But here is the interesting thing, my pulse oximeter (device used for monitoring oxygen saturation of hemoglobin) actually INCREASED by 6%. Therefore if anything it enhances the lung by increasing PEEP, and does not, in contrast to the BMJ's conclusion, contribute to pulmonary hypertension. QED.
So circular breath. Live long. AND Prosper. V