Thyroid Hormone and Sleep Quality

Whether you’re having difficulty falling asleep or staying asleep, thyroid health can have a profound impact on sleep quality and quantity. This is because the thyroid gland plays an integral part in the regulation of almost all the body’s metabolic function, thus, any imbalance in thyroid hormone levels can negatively affect sleep. In fact, studies assessing the beneficial effects of thyroid hormone replacement therapy in people with sleeping problems have shown positive results:
1. In people with sleeping disorders, the prevalence of thyroid hormone deficiency is very common. [233-244]
2. In patients with sleep apnea syndrome (breathing repeatedly stops and starts), thyroid hormone therapy effectively alleviates snoring only after one year of treatment. [245-246]
3. In patients with obstructive sleep apnea, T4 therapy for 4 months significantly reduces periods of absent breathing during sleep. [247]
4. T4 therapy in patients with subclinical hypothyroidism and obstructive sleep apnea is associated with less daytime sleepiness. [248]
5. One study reported that 50–100% of patients with hypothyroidism and obstructive sleep apnea showed an improvement in sleep-disordered breathing with T4 replacement. [249]
6. In patients with sleep apnea, thyroid hormone replacement therapy reverses symptoms and sleep-disordered breathing. [250]
7. In patients with sleep-disordered breathing associated with hypothyroidism, T4 replacement therapy alone significantly improves sleep apnea by reducing the total number of episodes of obstructive apnea and improving oxygen saturation during sleep. [251-252]
8. In patients with sleep apnea associated with hypothyroidism, combination of continuous positive airway pressure and low-dose T4 therapy improves sleep quality. [253]
9. In patients with obstructive sleep apnea associated with hypothyroidism, thyroid hormone replacement therapy significantly improves sleep quality especially in non-obese patients. [254]
10. In patients with newly diagnosed sleep-disordered breathing, T4 therapy alone improves breathing patterns, nocturnal hypoxia (diminished oxygen supply at night), and thyroid deficiency. [255]
11. In patients with hypothyroidism and sleep apnea, T4 replacement therapy significantly improves sleep respiratory abnormalities. [256-258]