Shorter Days, Signs of Fatigue: Trump Faces Realities of Aging in Office

With headline-grabbing posts on social media, combative interactions with reporters and speeches full of partisan red meat, Mr. Trump can project round-the-clock energy, virility and physical stamina. Now at the end of his eighth decade, Mr. Trump and the people around him still talk about him as if he is the Energizer Bunny of presidential politics.

The reality is more complicated: Mr. Trump, 79, is the oldest person to be elected to the presidency, and he is aging. To pre-empt any criticism about his age, he often compares himself to President Joseph R. Biden Jr., who at 82 was the oldest person to hold the office, and whose aides took measures to shield his growing frailty from the public, including by tightly managing his appearances.