The Empress Dowager, widow of the Emperor Showa, has had difficulty breathing since Wednesday evening and is on a respirator, the Imperial Household Agency said Thursday.
Agency officials said the 97-year-old Empress Dowager was not hospitalized as of Thursday evening, but is receiving treatment at her residence. There are no immediate plans to hospitalize her, they added.
Her temperature was normal at 36 degrees and her pulse was between 80 and 100 beats per minute, the officials said.
She was drawing 30 breaths per minute and her average blood pressure measured between 190 and 130 over 95-70, they added.
The Emperor and Empress have visited the Empress Dowager, according to the officials.