Every night, at the moment she started to fall asleep, a 77-year-old woman felt a sledgehammer pounding inside her head. It did not hurt. It jolted her awake and left her anxious, so she built a routine around avoiding it: stay awake on purpose until she was exhausted enough that the sledgehammer could no longer wake her. Her usual sleep onset drifted to around 4 a.m. Once she was finally asleep, she reported averaging about seven hours.
She had done this for 15 years.
