The former Hercules and Kull the Conquerer star revealed that he experienced vision problems and a constant "humming" in his head for years after the illnesses, which he recounts in his new memoir True Strength.
"Obviously, it completely turned my life around. I went from 14-hour days on the set to one hour a day for the next half of the season until I could slowly build myself up again," he told The Huffington Post.
"It was a good three years before I felt normal again, and over two years for the generator sound in my head to stop. It was like a low humming sound, 24 hours a day.
"I told my wife I never understood suicide until then. There would be people who wouldn't be as strong as I am - I'm a very strong-willed person - this would be too much for them to handle.
"It was horrible. I literally went from a guy in his 30s - in as good as shape as most athletes in their early 20s - to a guy who was 90 years old within seconds."
He went on to say that while he struggled with his condition, he has since come to regard the experience as a gift, adding: "It didn't kill me. It certainly made me stronger. It pushed me to become a bigger and stronger man - physically and mentally."
Sorbo recently signed up for a cameo role on ABC's new comedy Apartment 23 alongside Dean Cain.