The Thyroid

The thyroid gland is the “master controller” of metabolism.

About Hypothyroidism

Hypothyroidism, or an underactive thyroid gland, is a common condition.1 It is caused when the thyroid gland does not produce enough thyroid hormones. This under-production of hormones slows down the body’s metabolism, often leaving patients feeling cold, tired and depressed.2 If you suffer from hypothyroidism then you are also likely to notice you have gained weight, despite following a sensible diet and exercising regularly.1

Key symptoms of hypothyroidism

The symptoms of hypothyroidism are unpleasant and can affect a person’s self-esteem, work, and home and family life.1-4

Symptoms include:

  • Fatigue/drowsiness
  • Cold intolerance
  • Weight gain or increased difficulty losing weight (despite a sensible diet and exercise)
  • Depression
  • Constipation
  • Abnormal menstrual periods or fertility problems
  • Joint or muscle problems
  • Thin and brittle hair and fingernails, and/or dry flaky skin
  • Decreased libido

If left untreated, hypothyroidism can cause more serious complications and even become life-threatening. Severe complications of hypothyroidism include:

  • Slip into a coma1
  • Heart failure1
  • Severe life-threatening depression1
  • Coma1
  • An increased risk of Alzheimer’s disease in women 5

Who is at risk?

  • Women are generally more prone to developing hypothyroidism, especially during pregnancy, after giving birth and around the menopause6
  • The elderly generation6
  • People who have relatives with autoimmune disorders6
  • People with autoimmune diseases e.g., type 1 diabetes or rheumatoid arthritis6
  • People with manic depression6
  • Patients who have undergone radiation treatment or thyroid surgery6
  • White and Asian populations6

Diagnosing thyroid dysfunction

Many people remain undiagnosed with thyroid problems and suffer for a long time as their symptoms are confused with those of other conditions, such as depression or weight gain. 6 Thyroid dysfunction can be confirmed by your doctor through a simple blood test.6

If you are concerned that you could be suffering from problems with your thyroid gland, please discuss this with your doctor. To aid your consultation, download our Wellbeing Diary to help you keep a check of the symptoms you are experiencing, or try our short thyroid disorders symptom checker.

How hypothyroidism is treated

Treatment for thyroid dysfunction is straightforward, well-established, and highly effective.6 As there is no cure for hypothyroidism, the aim of treatment is to replace the missing thyroid hormones in the body.6 Appropriate medication, taken daily, should enable patients to live a symptom-free life.6

If you have been diagnosed with hypothyroidism, it is important to remember that treatment is a lifelong commitment and medication has to be taken every day, even when your symptoms are under control.6 This may seem a bit daunting, but by taking control of your condition and complying with your medication you should be able to remain symptom-free.6 It is advisable to see your doctor more frequently if any changes in your condition occur.

How thyroid hormones impact your heart

The heart is a major target of thyroid hormones.

Too little thyroid hormone as a consequence of an underactive thyroid (hypothyroidism) may cause:7

  • Increased levels of low-density lipoprotein (“bad”) cholesterol, total cholesterol, and triglycerides
  • Higher blood pressure
  • Low heart rate (less than 60 beats per minute)
  • Increased stiffness of the walls of the blood vessels
  • Increased strain on the heart

Even mild hypothyroidism worsens heart disease

Mild hypothyroidism affects 4–20% of the population and is more common in women than in men.8 Older people are more likely to suffer from a slightly underactive thyroid gland.6 If you have both heart disease and a slightly underactive thyroid then it is vital that your thyroid is returned to normal function. The presence of both diseases is associated with increased risk for death from heart disease.9

  1. Hypothyroidism: too little thyroid hormone. Available at Last accessed February 2022
  2. American Thyroid Association. Hypothyroidism. Available at Last accessed February 2022
  3. British Thyroid Foundation. Psychological symptoms and thyroid disorders. Available at Last accessed February 2022
  4. Poppe K, Velkeniers B, Glinoer D. The role of thyroid autoimmunity in fertility and pregnancy. Nat Clin Pract Endocrinol Metab 2008; 4: 394–405
  5. Tan ZS, Beiser A, Vasan RS et al. Thyroid function and the risk of Alzheimer disease: the Framingham Study. Arch Intern Med 2008; 168: 1514–1520
  6. American Thyroid Association. Hypothyroidism. Available at Last accessed February 2022
  7. Hormone Health Network. Hypothyroidism and heart disease. Available at Last accessed February 2022
  8. Razvi S, Weaver JU, Pearce SH. Subclinical thyroid disorders: significance and clinical impact. J Clin Pathol 2010; 63: 379–386
  9. Iervasi G, Molinaro S, Landi P et al. Association between increased mortality and mild thyroid dysfunction in cardiac patients. Arch Intern Med 2007; 167: 1526–1532


Date of preparation: February 2022