7 Surprising Facts About Your Body

There’s probably a lot you don’t know about your body’s form and function. Delight the guests at your next dinner party with these astonishing tidbits.

  1. Escaping gases cause your joints to crack. Your hips, shoulders and knees can sound off in a variety of ways. Sometimes tendons snap or rough surfaces of arthritic joints creak. The common knuckle-cracking sound stems from popping bubbles of oxygen, nitrogen and carbon dioxide in your joint’s fluids.
  2. Bacteria outnumber human cells 10 to one. Microbes live in your nose, mouth, skin, digestive system and reproductive organs. Some cause disease. But many others actually benefit your health. Scientists are working to understand the best balance and how to maintain it.
  3. Your blood vessels measure about 60,000 miles. Lay your arteries and veins end-to-end, and they’d cover a lot of ground. During your lifetime, your heart pumps about 1 million barrels of blood through them, at a rate of 1,800 gallons per day.
  4. Sweat doesn’t smell. Wonder why your gym bag suggests otherwise? Bacteria feed on fatty acids and other compounds in your perspiration. In the process, they convert the clear fluid into smelly gases.
  5. Women blink twice as often as men. Doctors don’t know why, exactly. But in one recent study, female subjects shut their eyes an average of 22 times per minute. That compares with about nine times for men.
  6. Your feet are more complex than you think. Each one con- tains 26 bones, 33 joints and more than 100 muscles, tendons and ligaments. Age, ill-fitting shoes and extra weight can put stress on them all, causing such problems as bunions, hammertoe and corns.
  7. A chemical called adenosine makes you sleepy. During the night, your body breaks this compound down. The longer you’re awake, the more it builds up in your bloodstream. High levels serve as a way to trigger rest when you need it.