I had a TIA at 28 working like that. Some people need warning signs and I definitely did as I thought I was invincible. I recovered physically in a few months but the shock took years; dying never occured to me. I get more work done now than I did then, working 4 hours standing behind a computer while spending the rest of the day walking in nature and thinking and having conversations via Skype with my peers. I believed then fast typing and iterating for long stretches of time was a thing that speeds up work and could do it for 18 hours a day: it is nonsense. Programmers who believe that have a lot to learn. They might be dead or worse before that though.