Were those physical shocks or an emotional shock that left you with a kind of Post Traumatic Stress Disorder? Or did you have heart problems, went into cardiac arrest, and the shock paddles had to be used?

I can understand why sudden loud sounds make you jump; I'm like that as well. I'm very sensitive to sound and have had to uproot myself and move several times over the past 10 years because of excessively noisy neighbors or loud traffic (boom cars, loud motorcycles, loud aftermarket exhaust systems on autos and motorcycles).

To strengthen your heart you need to exercise daily. Even walking 1/2 an hour a day helps. It also helps you deal with the stress of excessive noise exposure your body has to endure every day. There is something called "EMDR" (eye movement desensitization and reprocessing) therapy that is used for people who have suffered Post Traumatic Stress Disorder. Usually psychologists and / or psychiatrists facilitate the therapy.