Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
The average sperm cell swims at 8 inches per hour.
76
When you take a step, you are using up to 200 muscles.
886
Yawns are more contagious among people with closer relationships.
163
Most of us have microscopic, worm like mites named Demodex that live in our eyelashes and have claws and a mouth.
-137
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22