It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
The average sperm cell swims at 8 inches per hour.
76
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
Yawns are more contagious among people with closer relationships.
163
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
It takes about 20 seconds for a red blood cell to circle the whole body.
102
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
193