Long term effects?
When I was 13 I belonged to an Explorer Post, an adjunct of the Boy Scouts. Our sponsor was a local company that built closed-circuit television systems, and after hours we could go into their shop and use their machine tools, equipment, test benchs, etc. to build our own gear, fix stuff, whatever we wanted.
I brought in an old tube radio to see if I could get it working. Took off the cover, everything looked intact. Plugged it in, nothing lights up. I was going to unplug it to take the tubes out for testing when I grabbed the metal chassis to move it closer first. Unbeknownest to me, the power cord had frayed and the hot side was shorted to the chassis while the return was broken off completely. As I grabbed the case I simultaneously put my hand on the metal workbench, grounded well as it should be. The jolt stiffened my entire body, catapulting me about 10 ft straight back off the shop stool. After everyone came running and picked me up, I was okay except for a bruised tailbone and a burn on my hand, just like Tireguy. I didn't think much of the incident.
But after a couple days I started to feel warm all the time, not feverish, just warm like summer and I don't need a coat. Problem was, this was February in northern Indiana. We went to the doctor and told them what had happened, but they found nothing wrong. From that point on my metabolism ran way higher than it had, so I was warm winter and summer, high energy, never gained weight.
Now fast forward 35 years; I'll be 47 soon. Just this year I slowed way down, no energy, gained weight. I went to the doctor and they found my thyroid is running at only about 10%. The doctor speculates that after all those years of running in high gear, my thyroid just burned itself out. I started Synthroid a few weeks ago and I'm feeling better already.
And having never lost my fascination, I'm back to a tube preamp...
:-)
David