Years ago, I had an appointment for some therapy on my back. When I got there, they took my blood pressure, something they'd never done before. The lady looked shocked. She took it again and said, you need to leave here now, and go see your family doctor, or go to the emergency room. My BP was through the roof. Scared the bejeezus out of me. I'd never had any issues with it.
Long story short, I wound up at a Cardiologist, who put me through every test he could come up with, including going for a sleep study. Never found a specific cause, but I've been taking two little pills every morning ever since.
But, the sleep study.... Maybe they've changed in the last decade, but I had to go to the hospital and spend the night. They literally had about 17 electrodes stuck to all parts of my head and chest. Wires going everywhere. They had a CPAP machine beside the bed he wanted me to experiment with to get used to it. I was going to sleep for a while, and if I had too many "events", they would wake me up and have me use the CPAP thingy.
I was laying there thinking, you really think I'm going to sleep with 3 miles of wire wrapped around me. Eventually, I asked for, and received, half an ambien, which put me out. Next thing I knew, they were waking me up and asking if I wanted breakfast. Said I didn't have but about 2 events the whole night. I was soooo thankful, because I thought if I had to go to bed every night hooked up to that thing....I'd just go ahead and tell the Lawd to take me now.