Issues caused by abnormal thyroid levels include a rapid or slowed heartbeat, weight loss or gain, changes in menstrual patterns, constipation and abnormal blood cholesterol levels, according to Mayo Clinic. Abnormal thyroid levels occur either as hyperthyroidism or hypothyroidism, each having its specific effects in the body.
Thyroid hormone controls how the body uses energy, called metabolism, including calorie burning and heartbeats. The levels of this hormone have effects on nearly every part of the body, says WebMD.
Hyperthyroidism is a condition in which the thyroid gland produces more thyroid hormone than the body requires. This condition increases the rate of metabolism, resulting in a rapid and irregular heartbeat, nervousness, sweating and a sudden weight loss, notes Mayo Clinic. It results from thyroid inflammation, called thyroiditis, an autoimmune condition such as Graves' disease, and the growth of nodules in the thyroid, which increases the gland’s activity, states WebMD.
Hypothyroidism is a condition in which the thyroid gland produces less thyroid hormone than the body requires. It occurs mainly in women and interferes with the normal balance of body chemicals, causing health issues such as infertility, joint pain, heart disease and obesity, explains Mayo Clinic. Causes include the use of medications such as lithium and amiodarone, thyroid surgery, and thyroid inflammation or an autoimmune disease, causing the immune system to attack the thyroid gland, says WebMD.