Brain surgery to repair an aneurysm.
In his 2007 book "Promises to Keep," he describes passing out in a hotel room in Rochester in February 1988, where earlier that night he had given a speech at the University of Rochester. He recalls a "lightning flashing inside my head, a powerful electrical surge — and then a rip of pain like I'd never felt before." He was unconscious for five hours.
“He was unconscious for five hours.”
Definitely not long enough — by about 20 hours.