Overactive Thyroid Gland? Here are the Causes, Symptoms and Common Signs


Medically reviewed by

Bajaj Finserv Health


4 min read

Key Takeaways

  • Hyperthyroidism is a serious problem in India
  • Hyperthyroidism can affect normal heart function
  • The symptoms of thyroid conditions normally require treatment

Thyroid disorders are a common problem across the world. This is also the case in India. Around 42 million people in India are affected by thyroid disease [1]. In Cochin, a study showed that hyperthyroidism was present in up to 1.6% of subjects. Doctors say that 1 in 10 people have some type of thyroid problem. Conditions linked to this disease often go undiagnosed too. This puts many at risk of developing major complications down the line.

Read on to know all about hyperthyroidism and the signs to look out for.

What Is an Overactive Thyroid?

he thyroid gland produces tetraiodothyronine (T4) and triiodothyronine (T3). These are regulatory hormones that control metabolism in the body. They affect how your cells utilize energy. Ideally, a properly functioning thyroid gland ensures effective and efficient use of energy.

An overactive thyroid gland increases thyroid levels. It produces more hormones than the body requires normally. When your thyroid gland produces T3 or T4 or both in excess, it leads to hyperthyroidism. This increases the body’s metabolic rate, causing issues such as arrhythmia and weight loss.

What Causes an Overactive Thyroid Gland?

An overactive thyroid gland can occur due to a variety of reasons. Some of the common causes include the following.

Autoimmune Diseases

The most common is Graves’ disease. It stimulates the thyroid to create excess T4 hormone. This is the most frequent cause of hyperthyroidism.

Excess Iodine in the Body

It is a component of both T3 and T4. It influences the hormone levels in the body.


These could be present in the:

  • Ovaries
  • Testes
  • Pituitary gland
  • Thyroid gland


Thyroid nodules that are over functioning are related to adenomas, Plummer’s disease, or goiter. Adenomas are benign lumps that cause thyroid enlargement and produce excess thyroid hormone.


This is when the thyroid gets inflamed. This causes T3 and T4 to leak into your bloodstream, instead of being stored in your thyroid gland. The inflammation could be due to pregnancy or related complications, an autoimmune disorder and other reasons.

Additional Read: Thyroid Eye Disease: What is the Cause and How to Prevent it

What Are Commonoveractive Thyroid Symptoms?

There are many symptoms that can accompany an overactive thyroid. Since the symptoms are so varied, they can be difficult to diagnose.

Some of the symptoms of hyperthyroidism are:

  • High metabolic rate
  • Anxiety and/or nervousness
  • Irritability
  • High amount of nervous energy and/or tremors
  • High blood pressure
  • Chronic fatigue and/or muscle weakness
  • Heat sensitivity and low tolerance for heat
  • Mood swings
  • Insomnia and/or difficulty sleeping
  • Unexplained weight loss
  • Tachycardia or rapid heartbeat
  • Irregular menstrual cycles or patterns
  • Arrhythmia or irregular heartbeat

Medically, tachycardia occurs when your heart rate is more than 100 beats per minute. In comparison, a normal adult resting heart rate is between 60 to 100 beats per minute. Arrhythmia occurs when the heartbeat is out of sequence. It may beat too fast, too slow, skip beats, or add beats.

As you can see, there are many different symptoms of hyperthyroidism. It can be difficult to identify them on your own. So, consult a medical practitioner who will help diagnose whether or not you have an overactive thyroid.

Additional Read: Guide to Thyroid Symptoms: How Do Iodine Levels Affect Your Thyroid Gland?

What Are the Signs of Overactive Thyroid Gland?

Some signs and symptoms of an overactive thyroid gland require you to get medical attention immediately. These are:

  • Dizziness
  • Breathlessness
  • Tachycardia
  • Fainting
  • A swelling at your neck
  • Arrhythmia
  • Abnormal sweating

Crucial Thyroid Tests

Diagnosis can be done via different tests as follows.

Physical Exam

This involves examining you and your medical history for symptoms such as:

  • Arrhythmia
  • Unexplained weight loss
  • Localized swellings
  • Tremors

It may also include a physical examination of your thyroid gland to check for swelling or tenderness.

Blood Pressure Test

Elevated blood pressure is a common sign of an overactive thyroid.

Blood Test

It measures thyroxine and TSH (thyroid stimulating hormone) levels to confirm a diagnosis.

Cholesterol Test

If your thyroid is overactive, your metabolic rate may be high and your cholesterol levels will be lower.

TSH level Test

Thyroid stimulating hormone is a pituitary gland hormone. If your thyroid levels are high, your TSH would be naturally lower. If your TSH levels are much lower than normal, it could be hyperthyroidism.

Due to the variety of symptoms that present with an overactive thyroid, it’s important to consult a doctor. Trained professionals can diagnose and recommend thyroid tests easily. You can book a doctor consultation or schedule your tests on Bajaj Finserv Health. Find doctors that can recommend treatments to help you handle your overactive thyroid appropriately.

Published on 19 Nov 2021Last updated on 4 May 2022
  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3169866/
  2. https://pubmed.ncbi.nlm.nih.gov/19585813/

Please note that this article is solely meant for informational purposes and Bajaj Finserv Health Limited (“BFHL”) does not shoulder any responsibility of the views/advice/information expressed/given by the writer/reviewer/originator. This article should not be considered as a substitute for any medical advice, diagnosis or treatment. Always consult with your trusted physician/qualified healthcare professional to evaluate your medical condition. The above article has been reviewed by a qualified doctor and BFHL is not responsible for any damages for any information or services provided by any third party.


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