Wearing headphones for an hour increases the bacteria in your ear 700 times.
233
The brain receives 20% of the body’s oxygen and 25% of total body glucose utilization, despite it accounting for only 2% of a person’s weight (about 1.4 kilograms).
8
It is possible to go blind from smoking too heavily.
50
Men have larger hearts; women's hearts beat faster.
77
The human brain is insensitive to pain.
76
The average sperm cell swims at 8 inches per hour.
76
Your heart pumps about 2,000 gallons of blood each day!
53