Hypothyroidism: Here Are The Cause And Symptoms Of This Disorder

Among a wide variety of chronic illnesses, hypothyroidism is a fairly common disease. It is observed that women are diagnosed with hypothyroidism in larger numbers than men, as well as that a person’s susceptibility to hypothyroidism increases with age.

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Fundamentally, hypothyroidism can be understood as an ailment of the endocrine system of the human body, which affects the thyroid gland of the patient.

In patients diagnosed with hypothyroidism, the thyroid gland does not function to its full capability and is unable to produce enough of the hormone known as thyroid hormone that is required for a number of bodily functions.

Some of the important functions of thyroid hormone in the human body are:

  • Increases and maintains the basal metabolic rate (BMR) of the body.
  • These hormones aid in protein synthesis.
  • Synergistic action along with the growth hormone helps in regulating bone growth.
  • It is essential for correct development and differentiation of the cells in the body.

Because the thyroid hormone is important in maintaining BMR that is the basal metabolic rate, having hypothyroidism directly affects the body weight. This disease is likely to make the person obese. Or sometimes even leads to extreme weight loss. These are the common hypothyroidism symptoms.[1]

In this thyroid disorder, the body of the patient becomes deficient in both T3 and T4 thyroid hormones, leading to a wide range of complications. To understand more of hypothyroidism symptoms and its causes, we shall take a look at the following key aspects of this illness.

Cause of hypothyroidism

We all know that hypothyroidism comes with a host of problems that upset the regular functioning of the body.

The diagnosis of hypothyroidism is done based on the levels of TSH (Thyroid Stimulating Hormone) and T4 in the body, and is divided into the following categories:

TSH levels T4 levels Type of hypothyroidism
Normal Normal Thyroid function normal
Elevated Low Overt hypothyroidism
Normal/Low Low Central hypothyroidism
Elevated Normal Subclinical hypothyroidism

These conditions may arise due to any of the following factors, ranging from autoimmune diseases to radiation therapy:

1. Surgical procedures of the thyroid gland:

If a patient undergoes extensive surgical procedures that lead to the removal of a large portion of or the entire thyroid gland, it leads to a significant reduction/complete halt to thyroid production in the body.

In such a case, the patient must be administered with thyroid hormone externally for the rest of their lives to prevent the occurrence of hypothyroidism symptoms.[2]

2. Autoimmune illnesses:

Autoimmune diseases are characterized by the production of excess antibodies in the body that attack native cells, causing deterioration of organs.

In some cases, the antibodies end up attacking the thyroid gland, thereby interfering with its proper functioning.

3. Radiation therapy:

People who undergo radiation therapy for treatment of other illnesses like brain and neck cancer are also known to be diagnosed with hypothyroidism, due to the interference of radiation with the thyroid gland functioning.

Other less common causes:

Apart from the above mentioned, other rarely observed causes include congenital diseases, pituitary disorders as well as iodine deficiency.

Symptoms of hypothyroidism

The hypothyroidism symptoms include a longer list and are not just limited to weight gain, dry skin or chronic fatigue. In adults, both in men and women, the symptoms include:

thyroid gland
Thyroid Gland
  • The most prominent hypothyroidism symptom in women is an alteration in their menstrual cycle. Thyroid hormone is essential for the regularity in the menstrual cycle, and any abnormalities in the same can be attributed to malfunctioning of the thyroid gland.
  • Constipation and a slower heart rate than normal.
  • Depression
  • Dry hair and/or hair loss is a common symptom since thyroid hormones also work with growth hormone to promote growth. Any decrease in thyroid levels disturbs growth patterns.
  • Greater sensitivity to cold
  • Swelling of the thyroid gland (also known as goitre) is caused due to deficiency of iodine in the body and leads to abnormally low thyroid levels in the body.
  • Unexplained weight gain or sometimes even weight loss.
  • Carpal tunnel syndrome: a nervous condition characterized by pain, numbness as well as tingling sensation in the hand and arm of the patient.[3]

The symptoms to look out for in small children and infants

  • Abnormally/chronically cold hands and feet
  • Extreme drowsiness
  • Hoarse cry, spitting
  • Retarded growth (or none at all, in severe cases)
  • Low muscle toning
  • Persistent jaundice
  • Puffy face, stomach bloating
  • Swollen tongue

Relationship Between Hypothyroidism And BMR

So, first of all what is BMR (Basal Metabolic Rate)? BMR is the energy that is required by your body when it is at rest to perform all the functions. Now, what is the relationship between Hypothyroidism and BMR? So, here it is.[4]

  • Thyroid hormone regulates the metabolic process and is important for normal growth and development in functioning of better metabolism in adults.
  • Hypothyroidism due to reduced thyroid hormone results in hypometabolism which means reduced resting energy expenditure and hence leads to weight gain and increased cholesterol.
  • Thyroid hormone influences metabolism in a way that it controls the energy balance by regulating the energy stored and the energy spent.

Factors Affecting BMR in Hypothyroidism


Factors Effect on BMR 
Age Young age – high BMR
Height Tall and thin people – high BMR
Body composition The leaner tissue muscle has high BMR & more body fat has low BMR
Fever/stress Increases BMR
Environmental changes/ temperature Increase or decrease in temperature – increases BMR
Fasting/starvation/ malnutrition Lowers BMR

How To Lose Weight When You have Hypothyroidism

An individual with hypothyroidism gains weight because thyroid gland stops sending thyroid hormones into the bloodstream that is important for the body metabolism.

To improve metabolism and thereby to lose weight, the following steps can be considered.

  • Exercising regularly: Exercise will boost metabolism; it is good to start with yoga followed by other exercises. (this will boost metabolism, strengthen bones, build muscle)
  • Curb stress for better sleep: While the body is gaining weight there is a chance of stress and disturbed sleep is also one of the hypothyroidism symptoms, so meditation should be added in the daily routine, immediately after waking up and before sleeping.
  • Dietary Modifications: Inclusion of protein and fiber such as beans, peas, lentils, low fat cottage cheese, tofu, greek yogurt, one serving of white fleshed fish (cod, haddock pollock, flounder), poultry eggs, lean beef will help you keep your weight under control and also induces weight loss.

Ways To Increase BMR In Hypothyroidism

  • Intake of adequate proteins.
  • Having breakfast regularly at the right time.
  • Include moderate carb diet.
  • Inclusion of good fats in terms of nuts like walnuts, almonds, seeds like flax seeds, basil seeds etc.
  • Eat variety of fruits and vegetables.
  • Water intake of 2 to 2.5 litres.
  • Distributing a larger meal into small and frequent meals.
  • 7 to 8 hrs of sleep, regularly.
  • Doing yoga/meditation/ other exercises.
  • Restrict alcohol intake.

In hypothyroidism there will be less production of thyroid hormone which results in a low basal metabolic rate (BMR). Adding foods which improve BMR, weight loss, and lifestyle modifications are the key factors to manage this condition.

Relation Between Sleep Apnea And Hypothyroidism

Sleep Apnea is a sleep disorder, where breathing stops during sleep for a period of 10 seconds or longer, for a few times at night. It can be mild, moderate, or severe, depending on how many episodes of interrupted sleep a person experiences.

People who have hypothyroidism or an underactive thyroid are more likely to develop sleep apnea. About 4 in 10 people with an underactive thyroid is said to have sleep apnea. This usually causes a type of sleep apnea called obstructive sleep apnea (OSA), occurring when the throat is swollen and inhibiting breathing.[5]

Severe OSA can be present even with normal TSH levels if thyroid antibodies TPO and TG are high. Sleep apnea causes inflammation, which triggers other autoimmune conditions.

It is possible that sleep apnea is one of many environmental factors that can trigger hypothyroidism.


Hypothyroidism is a common disease that often affects middle aged and older women. But it is also true that this particular disease can affect anyone including infants. Initially the hypothyroidism symptoms are not really visible or known and hence it is common to be ignored.

But with time, hypothyroidism, if left untreated, could lead to a series of health problems like obesity, infertility, heart disease etc. Hence it is important to be well aware of these diseases before you become its victim.


Q. What is the thyroid gland? What are its main functions?

A. The gland of the thyroid is a butterfly-shaped, small gland that is positioned at the front part of the trachea.

The thyroid gland secretes the thyroid hormone which is responsible for regular growth, coordination of energy as well as supporting growth in the body.

Q. Are women more susceptible to hypothyroidism?

A. Yes, women are eight times more likely to be diagnosed with hypothyroidism or any other related thyroid disorder than men.

Q. What is primary and secondary hypothyroidism?

A. Primary hypothyroidism is caused due to increase in TSH hormones. In this case, the thyroid gland cannot release more thyroid hormones in response.

Secondary hypothyroidism is caused due to a decrease in levels TSH in the body. In this case, the thyroid gland does not receive the signal to produce thyroid hormones.

Q. How hypothyroidism cause weight gain in patients?

A. Due to a decrease in thyroid levels in the body, the metabolism switches modes, which means that in case of burning calories for growth and other activities, the metabolic rate decreases in order to conserve energy. In order to store energy, the body tends to store calories in the form of fat.

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