Hyperthyroidism makes the body speed up. It occurs when there is too much thyroid hormone in the blood ("hyper" means "too much"). Nearly 10 times more frequent in women, it affects about 2% of all women in the United States.
The most common cause of hyperthyroidism, Graves' disease, is caused by problems with the immune system and tends to run in families. It affects at least 2.5 million Americans, including Olympic athlete Gail Devers who won a gold medal in track after being diagnosed with and treated for Graves' disease.
Symptoms include:
fast heart rate
nervousness
increased...
The thyroid is a small, butterfly-shaped gland just below the Adam's apple. This gland plays a very important role in controlling the body's metabolism, that is, how the body functions. It does this by producing thyroid hormones (T4 and T3), chemicals that travel through the blood to every part of the body. Thyroid hormones tell the body how fast to work and use energy.
The thyroid gland works like an air conditioner. If there are enough thyroid hormones in the blood, the gland stops making the hormones (just as an air conditioner cycles off when there is enough cool air in a house). When the body...