It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
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
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
Stress can result in more headaches as a result of the body rerouting blood flow to other parts of the body.
92
Yawns are more contagious among people with closer relationships.
163
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99