Yawns are more contagious among people with closer relationships.
163
It takes about 20 seconds for a red blood cell to circle the whole body.
102
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
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
Every year your body replaces 98% of your atoms.
119
It would take about 1,200,000 mosquitoes to fully drain the average human body of blood.
217
Your thumb is about the same size as your nose.
124
One human hair can support 3 ounces.
191