Warren Buffett, who will retire by the end of the year, explained that the reason for his retirement decision is the physical effects of aging he is experiencing, the Wall Street Journal reported. Buffett said he didn’t really start getting old until he was about 90, but when one starts getting old, it's irreversible.Related NewsInflation Rate MoM for Apr in United States is 0.2%, higher than the previous value of -0.1%. The forecast was 0.3%.He conceded that he occasionally loses balance and sometimes even forgets people's names. His eyesight has also become less clear when reading newspapers.However, he emphasized that when opportunities arise, he can still maintain a sharp mind to make investment decisions.