President Bush underwent a routine 4 1/2-hour physical examination Wednesday, one he hoped would confirm his assessment that he is in tiptop shape. "I've never felt better in my life," Bush, 64, told reporters Tuesday after the White House announced he would undergo a battery of tests at nearby Bethesda Naval Hospital. He added, "I'll know better tomorrow." Described as routine, the examinations to be administered by a team of doctors included chest X-rays, hearing tests, an eye examination, an electrocardiogram, allergy and dermatology exams, urinalysis and blood tests.