It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
Every year your body replaces 98% of your atoms.
119
Yawns are more contagious among people with closer relationships.
163
The human brain doesn't stop developing until about 25 years old.
102
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
Your body is creating and killing about 2.4 million red blood cells per second.
17
The average sperm cell swims at 8 inches per hour.
76