Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Stress can result in more headaches as a result of the body rerouting blood flow to other parts of the body.
92
It takes about 20 seconds for a red blood cell to circle the whole body.
102
The average sperm cell swims at 8 inches per hour.
76
If you are cold you are more likely to be hungry because you use energy to keep warm.
143
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
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197