HOUSTON -- Former President George H.W. Bush remains in a Houston hospital on Christmas Day after experiencing shortness of breath two days ago.

Family spokesman Jim McGrath said Thursday that the 90-year-old Bush remained at Houston Methodist Hospital. McGrath said Bush is "still doing well," but he did not offer details.

McGrath has said Bush was hospitalized Tuesday evening as a precaution.

Bush is the oldest living former American president. He has a form of Parkinson's disease that has forced him to rely on a motorized scooter or wheelchair. But he's also skydived on at least three of his birthdays since leaving the White House, including a tandem jump for his 90th birthday in June.