Samir Rajab, editor-in-chief of the government daily al-Jumhuriya, wrote the 75-year-old "Mubarak's health has completely stabilised" and both his blood pressure and temperature, at 37C degrees, were normal on Thursday.
Mubarak was continuing to take antibiotics and vitamins but "refused to stay in bed and went out into the garden of his home on Thursday morning", Rajab said in an editorial on Friday.
But Prime Minister Atif Ubaid stood in for Mubarak at a religious ceremony Thursday evening after doctors advised the head of state to rest.
State television said that Ubaid would also replace Mubarak at prayers on Friday, the last Friday of the Muslim holy month of Ramadan, in which the head of state normally participates.
Mubarak abruptly halted a keynote speech to parliament for 45 minutes on Wednesday before he returned, still pale and hoarse, to finish his remarks.