Why the Two May Occur Together

Although researchers are still trying to determine why sleep apnea and hypothyroidism may occur together, some have highlighted several possible explanations, such as:

• Having hypothyroidism may cause certain substances to build up in the soft tissues of your throat.
• The condition may also weaken the muscles that help keep your airway open; and, because hypothyroidism slows your metabolism, it may lead to weight gain in the neck area. All of these may cause your upper airway to narrow and make breathing more difficult while you’re asleep.
• Repeated drops in oxygen levels that occur during sleep apnea may affect thyroid health and could trigger ongoing inflammation. Plus, some of the same immune cells and inflammatory chemicals active in sleep apnea are also involved in Hashimoto’s thyroiditis.
• Chronic inflammation associated with sleep apnea may contribute to thyroid dysfunction in some people. But more research is needed to fully understand this connection between the two conditions.
• Hypothyroidism can weaken the muscles involved in breathing and make the brain less sensitive to low oxygen and carbon dioxide levels.

How Hypothyroidism May Affect Sleep Apnea Severity

The relationship between hypothyroidism and sleep apnea is not fully understood, and it remains unclear whether one condition directly causes the other.

That said, some studies have noted some interesting characteristics when the two conditions occur together. For instance, one study found that people with hypothyroidism had more episodes of interrupted breathing when sleeping than people with normal thyroid function.

During the study, those with an underactive thyroid experienced about 32 breathing interruptions per hour, compared with fewer than two per hour in those without the condition. Likewise, they had lower oxygen levels, too.

The oxygen saturation for those with hypothyroidism dropped to about 81 percent, compared with 93 percent in people without an underactive thyroid. These drops in oxygen happen because the airway becomes blocked, causing breathing to slow or stop throughout the night.

These findings suggest that hypothyroidism may be linked to more severe breathing and oxygen problems during sleep, but more research is needed to confirm the relationship.

How Both Conditions Are Treated

If you’re diagnosed with sleep apnea, the first line of treatment is usually a continuous positive airway pressure (CPAP) device. Your healthcare team may also recommend lifestyle changes, a change in sleeping positions, and ways to manage chronic health conditions.

Meanwhile, hypothyroidism is usually treated with hormone replacement therapy, typically with a medication known as levothyroxine. This medication helps regulate your hormones and can eliminate your symptoms. But it may take some time to get the dosage right.

Plus, if you have sleep apnea as well, this medication could be beneficial in addressing both conditions. One study found that treating hypothyroidism with thyroid hormone replacement improved or even reversed sleep apnea symptoms in many of the people studied.

That said, this treatment doesn’t work for everyone. So, some people may still need to use their CPAP machine to treat their sleep apnea. Your healthcare provider can help you determine what’s right for you.

Complications of Sleep Apnea and Hypothyroidism

Left untreated, both sleep apnea and hypothyroidism can lead to complications. That’s why it’s so important to see a healthcare provider for the appropriate testing, especially if you suspect one or both of the conditions. Here are some complications that can occur without treatment:

If you suspect that you have hypothyroidism, sleep apnea, or both, talk to your healthcare provider. They can discuss your next steps and put together a treatment plan if one is needed.