It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
Yawns are more contagious among people with closer relationships.
163
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
Enamel is hardest substance in the human body.
61
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
The human brain doesn't stop developing until about 25 years old.
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