The Korea Times reported that the 36-year-old star reflected on his journey during an appearance on the YouTube channel Fairy Jae Hyung, saying he had previously pushed his body to the limit in pursuit of productivity and physical fitness.

“There was a time when, out of three hours to sleep, I would rest for just one and use the rest to work out,” Kim recalled. “Now I sleep properly because I think about my health. I’m much healthier now. The time I took off during treatment gave me many good things.”

According to the U.K.’s National Health Servicenasopharyngeal cancer is a rare disease affecting the part of the throat that connects the back of the nose to the mouth, known as the pharynx. Around 260 people are diagnosed with it each year in the U.K. Early symptoms can include nosebleeds, facial numbness, or hearing loss.

Because the nasopharynx lies close to the brain, untreated cases can spread rapidly. While surgery is difficult in this area, radiation therapy and chemotherapy are generally effective, particularly when detected early.

Medical experts warn that chronic sleep deprivation can weaken the immune system, disrupt hormone balance, and elevate cortisol, which is the body’s primary stress hormone, potentially increasing the risk of illnesses, including cancer. Adults are advised to get seven to nine hours of sleep each night to help the body repair and strengthen its immune defenses.

Experts also recommend gradually extending sleep time instead of relying on “catch-up sleep” during weekends, which can disrupt the body’s circadian rhythm.

Kim said his illness taught him to slow down and value health over achievement.

“Even the strongest body needs rest,” he said, a message that has resonated deeply with fans inspired by his resilience.

Kim, 36, began his career as a model before transitioning to acting, gaining recognition in “White Christmas” and rising to fame with “A Gentleman’s Dignity,” “School 2013,” and “The Heirs.” He later starred in “Uncontrollably Fond” and the action film “Master” in 2016.

When he was diagnosed in 2017, doctors reportedly told him that in the worst-case scenario, he might have only six months to live, according to The Times of India. He was declared fully recovered in 2019.