Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
When you take a step, you are using up to 200 muscles.
886
After age 30, the brain begins to lose about 50,000 neurons per day - shrinking the brain .25% each year.
55
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
The human brain doesn't stop developing until about 25 years old.
102
Your heart will pump about 212 million liters in its lifetime.
26
Women have about four times as many foot problems as men; lifelong patterns of wearing high heels often are the culprit.
111
It would take about 1,200,000 mosquitoes to fully drain the average human body of blood.
217