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.
To put this in context, prior research has shown that staying awake for 24 hours in a row impairs performance on par with legal intoxication with alcohol (for driving), and six hours of sleep per night for two weeks causes a similar level of impairment as staying awake for 24 hours, Cohen says.