In the manga's 1,208th chapter titled "Foliage", series protagonist Ippo Makunouchi visited the doctor and discussed his concern about chronic traumatic encephalopathy (CTE), which is also known as "punch drunk". This behavior affects people who had multiple head injuries, something that is common in the sport.
The current editor of the series revealed via J-Cast News that he was also shocked when he learned Ippo's retirement announcement, but confirmed that Ippo has plans to retire. The editor also heard some criticism about the announcement and assured fans that Morikawa is still dedicated to producing the series that his fans support.
[Source: Anime News Network]