What Hyperthyroidism Looks Like

When your body produces too much thyroid hormone, everything speeds up. In fact, your metabolism may increase by as much as 60 to 100 percent — as much as double its normal speed. As you might imagine, this can produce profound effects on how your body functions and on how you feel.

But as with hypothyroidism, these symptoms may develop slowly. When you first become hyperthyroid, you may feel fine and have no symptoms at all. But gradually, as your thyroid gland becomes increasingly active, you will start to notice changes that will become more bothersome over time.


In healthy people, it's normal for your heart to speed up during exercise, activity, or stress. But in people with hyperthyroidism, your heart may beat this fast even when you are sitting still or asleep. If your heart rate goes above 100 beats per minute, you are said to have tachycardia. A sustained rapid heart rate always warrants medical attention.

Your Heart

Most people with hyperthyroidism will notice that their heart is beating faster, even during periods of rest. In some people, the heart rate speeds up to more than 100 beats a minute. In older people, a sped-up heart can lead to irregular rhythms, which can be dangerous in people with other forms of heart disease.

The effects on your heart can be easily measured. Your blood pressure will be higher than normal. Your pulse will be considerably faster. In some people, a sped-up heart can feel as if it is beating out of their chest. The increase in your heart rate can cause other symptoms, too, such as headaches, breathlessness, and dizziness.

Nervousness and Irritability

People with an overactive thyroid frequently feel on edge, nervous, and anxious. They may have trouble catching their breath. They may fidget and experience tremors in their hands. In their dealings with other people, they may be irritable and argumentative. The nervousness often causes difficulties with sleep, leading to frequent bouts of insomnia. Doug says he remembers feeling very agitated.

All his life, Doug always felt as if he had energy to burn. But at thirty-nine, his energy levels seemed to spike. He was quickly agitated, and noticed that he was sweating more than usual while playing basketball. He also started having occasional heart palpitations and wondered if he was having a panic attack. Looking back, he remembers many times when he felt as if he was on a caffeine buzz. Now he wonders if it was his overactive thyroid.

Weight Changes

Many people with hyperthyroidism experience weight loss and changes in their appetite. These changes in weight and appetite are the result of a revved up metabolism that causes your body to burn up energy more rapidly.

Most people notice an increase in their appetite as their body's energy needs increase. But even with the extra food they're eating, many of them may still be losing weight. Other symptoms of hyperthyroidism, including diarrhea and heavy sweating, can compound your weight loss, too.

Still others with hyperthyroidism will lose all interest in eating and rapidly lose weight. If this occurs in teenagers, they may be mistakenly diagnosed with an eating disorder.

Less common, some people's appetites surpass their stepped up metabolic rates, resulting in weight gain. An increase in weight may also be caused in part by extreme exhaustion, which can make it hard for you to exercise or stay active.

The GI Tract

Hyperthyroidism causes your gastrointestinal tract to digest foods more quickly. The excess hormone causes an increase in the contractions in your bowels. As a result, you may notice more frequent bowel movements or, in more severe cases, diarrhea.

The Eyes

The eyes are sensitive to the effects of thyroid hormone, and patients with severe hyperthyroidism will develop a stare in which the eyes appear to have a wide-eyed, startled appearance.

This condition is common in people who have Graves' disease and is called thyroid eye disease, or infiltrative ophthalmology. With thyroid eye disease, the eyeball bulges. This bulging is caused by swelling in the muscles around the eyes, which makes the eyeball protrude. Some hyperthyroid patients may have trouble closing their eyes completely. With the eyeball constantly exposed, the eye can become red and irritated.


Early on, irritations of the eye may be mild and mistaken for allergies, especially since many of the symptoms are most noticeable in air-conditioning, hot-air heating, and windy climates. You may also have trouble wearing contact lenses because they are irritating. If these symptoms occur with other symptoms, ask your doctor to consider your thyroid.

In more severe cases, the eyes lose the ability to move in sync, and you may experience double vision. Many people may also notice that their eyes are more sensitive to light, and that they frequently feel gritty, dry, and irritated.

Enlarged Thyroid Gland

An overactive thyroid causes your thyroid gland to develop a goiter, which means the gland has become enlarged. If you put your hand on the goiter, you may notice a vibration called a thrill, caused by an increase in blood flow to the thyroid.

Emotional Disturbances

Hyperthyroidism can lead to a host of emotional disturbances that produce symptoms of depression and mania. In extreme cases, it can cause disordered thinking or delusional thoughts. Some people may actually receive a psychiatric misdiagnosis for these extreme mood swings.

Many of the emotional problems come from the sheer exhaustion that results from having hyperthyroidism. The body becomes exhausted by the increased energy burn, which is made worse by lack of sleep.


If you don't have your menstrual period for three months or more, call your doctor. Amenorrhea — the absence of regular periods — may also be caused by polycystic ovarian syndrome or Cushing's disease, an overproduction of the hormone cortisol. Women who exercise in excess or who are under extreme stress also may stop menstruating.

Other Changes

People who have hyperthyroidism are often intolerant of the heat and may sweat profusely in temperatures that healthy people consider comfortable. Their skin may feel moist to the touch. They may also notice muscle weakness, especially in the thighs and the upper arms or shoulders. In addition, they may bruise more easily, lose hair, and experience frequent, loose stools.

Hyperthyroidism frequently causes changes in your hair, skin, and nails. Many people notice a thinning of the skin. The excess perspiration may cause a rash. Hair may become finer and softer, and you may also notice hair loss on your scalp. Fingernails may grow more rapidly and separate from the nail bed.

Women with hyperthyroidism may notice their periods are lighter and may even skip periods. Men may experience erectile dysfunction. Both men and women may notice a drop in libido. Because of these effects on sexual function, hyperthyroidism can cause fertility problems for couples trying to conceive.

Left untreated, hyperthyroidism can lead to serious consequences. Excess thyroid hormone can make it hard for your bones to take up calcium, which can lead to osteoporosis. The impact on your heart can lead to heart failure, which occurs when your heart can't pump enough blood to the organs, resulting in death. You can also develop dangerous arrhythmias.

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