Can Hypothyroidism Cause Obstructive Sleep Apnea?

Sleep Apnea and Hypothyroidism

man with sleep apnea and CPAP in bed
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For individuals with sleep-disordered breathing, the cause of their obstructive sleep apnea can occasionally be somewhat elusive. Although it may not be a common contributor, hypothyroidism may surprisingly play a role. 

What Is Hypothyroidism and How Does It Impact Breathing?

Hypothyroidism refers to the inadequate secretion of thyroid hormones by the thyroid gland in the neck. This is sometimes referred to as having an underactive thyroid.

When hypothyroidism is present, there may be changes within the upper airway that lead to difficulties breathing during sleep.

How Are Hypothyroidism and Obstructive Sleep Apnea Related?

Like hypothyroidism, obstructive sleep apnea is a relatively common disorder in the general population. Patients with obstructive sleep apnea often experience symptoms including excessive daytime sleepiness, apathy, and feeling lethargic. These symptoms are also common in hypothyroidism, making the two disorders difficult to tease apart based on a patient's history and physical. 

In addition, patients with hypothyroidism may be at greater risk for developing obstructive sleep apnea, due to multiple factors involving respiration, such as a decreased ability to respond to chemical changes within the blood and even damage to the nerves or muscles involved in breathing. In addition, hypothyroidism may contribute to obstructive sleep apnea through enlargement of the tongue (called macroglossia) or disruption of the muscles that control the upper airway.

Finally, patients with hypothyroidism are at risk for obesity, another factor that contributes to obstructive sleep apnea. 

Treating the Source of Obstructive Sleep Apnea

Hypothyroidism is relatively easy to diagnose and treat based on the results of blood tests measuring various indicators of thyroid function.

For those already diagnosed with hypothyroidism and symptoms of sleep apnea, a sleep study can help determine whether sleep apnea is present. During a sleep study, healthcare providers will monitor your sleep either in a lab or at your home using portable equipment. 

Patients with symptoms of sleep apnea who are either referred for testing or have been officially diagnosed may wish to ask their physicians to order a blood test to analyze their thyroid levels, especially if their symptoms persist despite appropriate sleep apnea treatments. Sleep apnea is most commonly treated with continuous positive airway pressure (CPAP) therapy.

In addition to the symptoms that overlap with sleep apnea, there are some additional symptoms that can make a diagnosis of hypothyroidism more likely. These include:

  • Sensitivity to cold
  • Constipation
  • Dry skin
  • Brittle nails
  • Hair loss
  • Unexplained weight gain
  • High cholesterol
  • Irritability
  • Sexual dysfunction
  • Slow heart rate
  • Irregular uterine bleeding

Fortunately, if hypothyroidism is causing sleep apnea or breathing difficulties, it will improve with thyroid hormone replacement. This is typically taken as a pill called Synthroid (levothyroxine)


Skatrud J et al. "Disordered breathing during sleep in hypothyroidism." Am Rev Respir Dis 1981;124:325.

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