Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Poor eyesight (myopia) is associated with higher IQ.
232
Your heart will pump about 212 million liters in its lifetime.
26
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
It takes about 20 seconds for a red blood cell to circle the whole body.
102
If you are cold you are more likely to be hungry because you use energy to keep warm.
143
The human brain uses approximately as much energy as a 10 watt light bulb.
120
There are times when you're walking that the pressure on your feet exceeds your body weight, and when you're running, it can be three or four times your weight.
62