President Lincoln was plagued by insomnia, sleep deprivation and nightmares with the war raging, the budget rising, battlefield losses soaring, patronage decisions pending and reelection worries.
When he couldn’t sleep, he would often walk to the bedrooms of his secretaries, who lived at the White House. John Hay and John Nicolay had rooms directly across the hallway from each other.
The president would wander down the hallway, and the three would laugh late into the night.
Source: Presidential Courage: Brave Leaders and How They Changed America 1789-1989 by Michael Beschloss