Glen, shingles is certainly not life-threatening, but people who get it in their eyes sometimes go blind. People can also be left with long-term nerve damage and pain. Personally, I began feeling much better 2 weeks after diagnosis and starting the anti-virals. I think I was lucky, but I still felt wiped out for those 2 weeks. I am still getting some mild discomfort, principally itching. I am training regularly, even did a Parkrun last Saturday, but not notching up any PBs (no change there, then.)