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Astigmatism is the most common vision problem. It may accompany nearsightedness or farsightedness. It is usually caused by an irregularly shaped cornea, but sometimes it is the result of an irregularly shaped lens. Either type can be corrected by eyeglasses, contact lenses, or refractive surgery.
Pregnant women usually experience a heightened sense of smell beginning late in the first trimester. Some experts call this the body's way of protecting a pregnant woman from foods that are unsafe for the fetus.
The immune system needs 9.5 hours of sleep in total darkness to recharge completely.
Human kidneys will clean about 1 million gallons of blood in an average lifetime.
People with high total cholesterol have about two times the risk for heart disease as people with ideal levels.