A hyperactive thyroid causes the body to burn energy faster than normal, resulting in a condition called hyperthyroidism. The thyroid gland is responsible for regulating the body's metabolism; when it secretes too much hormone, all the other organs in the body become hyperactive. More than 2 million people in the United States are affected by hyperthyroidism, the majority of whom are female, according to the New York Thyroid Center. A hyperactive thyroid can cause many side effects, ranging from mild to severe.
Restlessness and Irritability
Because metabolism is heightened in people with a hyperactive thyroid, several mental disturbances may result. Irritability and anxiety are common symptoms, often resulting in nervousness and restlessness. A person with hyperthyroidism may have difficulty concentrating or holding thoughts. Rapid mood swings have also been documented. A hyperactive thyroid may also cause sleep disturbances, such as insomnia or difficulty falling asleep, explains the National Endocrine and Metabolic Diseases Information Service.
Weight Changes
A person with a hyperactive thyroid may experience a sudden increase in appetite and may eat more food than normal. Even while eating more food, however, a person with hyperthyroidism may inexplicably lose weight, reports MayoClinic.com. Changes to bowel movement frequency, such as increased bowel movements or diarrhea, may also occur.
Muscle Spasms
A hyperactive thyroid may cause tremors or spams in the hands or other muscles. This can lead to feelings of muscle weakness or trembling. A rapid heartbeat, sometimes exceeding 100 beats per minute, may also occur, as well as irregular or pounding heartbeats. Changes to blood pressure are another common symptom, as are problems with vision or eye irritation, according to MedlinePlus.
Gender-specific Effects
Men suffering from a hyperactive thyroid gland may develop breasts, a condition known as gynecomastia. The breast smay become tender or painful. Women with hyperthyroidism may develop irregular menstrual cycles, or menstrual periods that become very light and occur less frequently. In some women with hyperthyroidism, the menstrual periods may stop completely, explains the New York Thyroid Center.
Additional Symptoms
The increased metabolism caused by a hyperactive thyroid may result in excessive sweating and the inability to tolerate warm temperatures. Nausea and vomiting may also occur. In some causes, the thyroid may swell, causing a goiter, or lump on the back of the neck. In other cases, swelling may occur behind the eyes, causing the eyes to protrude from the face. Generalized itching all over the body, known as pruritus, is another side effect. Some people with hyperthyroidism suffer from hair loss, irregular fingernail growth and thin, delicate skin, MedlinePlus reports.
