On April 16 episode of KBS' television show 'Hits Song', HeeChul talked about his past.

HeeChul said, "Well, I used to smoke back then, and that is something that I really regret doing."
He continued, "I smoked so much that I completely damaged my bronchial tubes. They don't function well anymore."

HeeChul said, "I can't even have hot soup anymore. It's all because I smoked too much."
He added, "It's been over 10 years since I've stopped smoking now. If I could go back in time, I would never start smoking."

(SBS Star)