(CNN) - Sen. John McCain will give select members of the media a three-hour glimpse at his medical records Friday.
If elected, McCain, the 71-year-old presumed Republican nominee, would be the oldest president of the United States, beating Ronald Reagan by three years on inauguration day.
Presidents and candidates have released records in the past, and some, like McCain, have stipulated that the records cannot leave the room.
McCain, a cancer survivor, is particularly under pressure to prove to the public that he is physically fit for office.
Democratic candidates Sen. Barack Obama and Sen. Hillary Clinton have not made their health records public, but whoever secures the nomination probably will, said David Mark, senior editor at Politico.
McCain has told reporters not to expect surprises, and that doctors told him everything is fine.