It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
An average heart beats 100,000 times a day, pumping some 2,000 gallons of blood through its chambers. Over a 70-year life span, that adds up to more than 2.5 billion heartbeats.
73
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
The average person's skin weighs twice as much as their brain.
131
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
The human brain uses approximately as much energy as a 10 watt light bulb.
120
Every year your body replaces 98% of your atoms.
119