★★★★★
While I don't know if this is capable of causing a lasting effect or long-term cure, I know it works for me to drop my BP, at least for a little while. Its something that I do, when I see my BP is a little too high for comfort. I, of course, closely monitor my BP to make sure it's staying in check and don't blindly trust anything.
Deep heavy breathing. Exhale everything from the lungs, then sharply/quickly inhale til lungs are full, quickly exhale til the lungs are empty, Do this a few more times, then on an inhale, hold it. It usually causes me to get lightheaded when I hold it, this is the feeling I'm aiming for. I Hold it for a good little bit. Then do it again. When I do this, I'm trying to completely saturate my blood with oxygen as much as I possibly can. I usually quickly feel very relaxed.
In my experience this is a good quick way to drop my BP a good 15-20 points off the top and at least 5 off the bottom and usually more than enough to get my BP in a safe range. Last time I did it, I was around 155/91 and dropped it to 131/84 before I stopped monitoring it, took me about 10 minutes to get there from the 155/91. May have went lower, I'm not sure.
Breathing Technique
★★★★★