Structure of Haemoglobin: Haemoglobin is an aggregation of four globular proteins (typically two alpha and two beta subunits), each with an embedded haeme group. Each haeme group allows the binding of an oxygen molecule.
Here's another intriguing case from the Guinness World Records. In 1964, a 17-year-old high school student named Randy Gardner beat the world record for sleep deprivation by staying awake for 264 hours (11 days) without using any stimulants.
The apnea-hypopnea index, or AHI, is an index used to assess the severity of sleep apnea based on the total number of complete cessations (apnea) and partial obstructions (hypopnea) of breathing occurring per hour of sleep. By definition, these pauses in breathing must last for at least 10 seconds.