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.
Forty winks: Photographer Tyler Shields, 28, claims he stayed awake for 968 consecutive hours but Guinness Book of Records won't recognise his stunt saying it's too hard to prove. During the wide-eyed marathon, Shields said he overcame fevers, headaches, eye pain and the loss of feeling in his legs.