Think about more mundane things... kidney stones or a burst appendix can cause sudden debilitating pain at any age with little or no warning. FWIW, I've buried a friend (runner, skinny, all the "right" lifestyle & diet stuff) who had a sudden MI at 38. See this thread... another runner and lap swimmer in his 30's in "excellent shape," though dieting. (It turnded out ultimately that the diver in that thread had a heart problem - remained undetected for another six months!) As the saying goes, stuff happens... it's just something you have to accept as part of the risk of swimming or diving alone.I've heard stories of people becoming paralyzed whie diving, or typically as they surface from an AGE or DCS. I try to minimize that possibility by doing very slow ascents and not going into deco when alone.
Other than that, I guess the risk is having a heart attack? But I'm only 36.
Again, by all means take precautions to mitigate those things you can control when solo diving, just realize no one is immune to the "undeserved event" and that there is that added risk when no one else is around.
I still do a bit of solo diving, but less and less as I get older... once the youngest is a taxpayer I'll likely do it a bit more again
Rick