High thyroid levels, also known as hyperthyroidism or overactive thyroid disease, occurs when the thyroid gland makes and releases too much thyroxine into the blood. The thyroid gland located in the front of the neck produces thyroxine hormone. Thyroxine plays a key role in controlling the metabolic processes of the body including heart rate and the speed at which the body burns calories. According to the American Academy of Family Physicians, more than 70 percent of hyperthyroidism cases are caused by a disorder called the Grave's disease. According to MayoClinic.com, the effects of high thyroid levels include Graves’ opthalmopathy, changes in heartbeat and weight loss.
Graves' Opthalmopathy
MayoClinic.com lists Graves’ opthalmopathy, a condition in which the tissues and muscles behind the eyes swell up and push the eyeballs forward making them bulge out of their orbits, as one of the side-effects of high thyroid levels. The American Academy of Family Physicians says that in this condition, the front surfaces of the eyeballs feel dry and get red and swollen. Individuals also experience double vision, light sensitivity, excessive tearing or discomfort in the eyes, and reduced eye movement.
Changes in Heartbeat
MayoClinic.com reports changes in heartbeat as a side effect of high thyroid levels and also says that individuals may have tachycardia or rapid heartbeat, which means that the heart beats at a rate of more than 100 beats a minute. The individual may also have arrhythmia, in which the heartbeat becomes irregular, and palpitations or pounding of the heart.
Weight Loss and Other Effects
According to MayoClinic.com, high thyroid levels may also have other side effects such as weight loss. MayoClinic.com says that sudden weight loss may occur even when the appetite and diet of the individual remains the same or may even increase. Other side effects of high thyroid levels include trembling in the hands and fingers, sweating, an increased sensitivity to heat, changes in bowel patterns, fatigue, muscle weakness and difficultly sleeping. An enlarged thyroid gland can appear as a swelling at the base of the neck, along with changes in menstrual patterns in women, nervousness and irritability.
