Underactive thyroid, called hypothyroidism, occurs when the thyroid gland stops producing a sufficient amount of thyroid hormones. Thyroid hormones help to regulate metabolism--which regulates processes throughout the body. The U.S. National Library of Medicine (NLM) says that when the thyroid gland becomes inflamed, often from an autoimmune disease, hypothyroidism may result. Hypothyroidism is easily diagnosed with a blood test and treated with medication. But, it's important to recognize the warning signs and get tested.
Initial Physical Symptoms
Some of the first signs of hypothyroidism include some physical warning signs, like unexplained weight gain and a weak feeling in the muscles. Many people experience pain in the muscles and joints, says the NLM, and women may notice that their menstrual periods become heavier. The skin, hair and fingernails are often affected, becoming dry, thin and breaking easily. Many people may also suffer from constipation.
Initial Behavioral Symptoms
Underactive thyroid can not only affect the way you feel, but the way that you behave and think. Depression is a common sign of underactive thyroid, says the NLM. Many people feel extremely fatigued and exhausted because of slowed metabolism. They may also find that they are more strongly affected by the cold, and have difficulty getting and staying warm.
Later Symptoms
As underactive thyroid progresses and the body's metabolism remains slower than normal, symptoms can become more severe and obvious. The hands, feet and face can become swollen, and the voice may be affected and sound hoarse. Other affected senses include smell and taste, which may be less sensitive than usual. The skin may begin to appear thicker, while people may have more difficulty speaking because their speech is slower than normal. The Mayo Clinic reports that people with hypothyroidism may also have difficulty concentrating and paying attention, and the memory may begin to suffer.
