It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
When you take a step, you are using up to 200 muscles.
886
Your body is creating and killing about 2.4 million red blood cells per second.
17
An average heart beats 100,000 times a day, pumping some 2,000 gallons of blood through its chambers. Over a 70-year life span, that adds up to more than 2.5 billion heartbeats.
73
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Women have about four times as many foot problems as men; lifelong patterns of wearing high heels often are the culprit.
111
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515