The Japanese call it pok-kuri. Filipinos call it bangungot or batibat. For the Hmong people of Vietnam and Laos, it is the tsob tsuang. Taiwanese men, some of whom wear lipstick to bed in order to deceive nocturnal ghosts, claim it is the phi am or ‘widow ghost’, a malevolent spirit who, much like Freddy Krueger or one of the supernatural ghouls from The Grudge, steals away the souls of young men in their sleep. All these names refer to the same thing: Nightmare Death Syndrome.
Your very first question is: what the hell is nightmare death syndrome? Is it really what it sounds like, death by nightmare? The answer, sadly, horrifyingly, is yes. You can actually die from fear while having a nightmare.
In the early 20th century an American anthropologist wrote about the Bontoc’s belief in the li-mum, or “fiendish nightmares…[caused] by sitting on the sleeping individual’s breast and stomach.” Similarly, the English word nightmare originally referred to a “mare”, a female spirit, who was believed to suffocate sleeping victims.
In 1960, Dr. Gonzalo Aponte was called to the US Naval Hospital in Guam to investigate the deaths of 11 Filipino sailors, who all seemed to have died inexplicably in their sleep after days of complaining about nightmares. Though the autopsies turned up few concrete details, Aponte looked into the case further and found reports regarding Sudden Unexplained Nocturnal Death (SUND) dating back as far as 1917.
The newest case is an aggregate of deaths spanning four years and claiming 18 members of a preliterate, animist Laotion mountain society called the Hmong.
Everything from pancreatis and nutritional deficiencies to congenital problems in the heart’s anatomical structure have been blamed. But the end result is always the same. A seemingly healthy person, with no adverse medical history, dies from very sudden cardiac arrythmia.