The thyroid is a small butterfly-shaped gland found in the neck. It produces thyroid hormones - T4 (thyroxine) and T3 (triiodothyronine) - which help control your metabolism, heart rate, body temperature, and energy levels.
When the thyroid malfunctions, it can become underactive - known as hypothyroidism, or overactive - known as hyperthyroidism. Both hypothyroidism and hyperthyroidism can affect sleep.
Lisa Artis, deputy CEO of the Sleep Charity partnered with Simba, warned that this includes how much sleep you’re able to get at night. “Waking up too early can point to an under or over active thyroid,” she said.
This is because thyroid hormones play a key role in maintaining the circadian rhythm, which regulates the sleep-wake cycle. Incorrect hormone levels can disrupt this rhythm, leading to early morning waking.
Other ways in which these disorders can affect sleep include:
- Hyperthyroidism - this often causes more noticeable sleep disturbances because it speeds up metabolism, leading to insomnia, restlessness, night sweats, and a racing heart - you may feel “wired”, but exhausted
- Hypothyroidism - this can lead to excessive sleepiness, fatigue, and trouble staying awake during the day due to a slowed metabolism - it can also cause sleep apnoea, which disrupts sleep quality.
If the issue is trouble falling or staying asleep, hyperthyroidism usually has a bigger impact, according to Lisa. If it’s feeling constantly tired, hypothyroidism is generally more to blame.
Hyperthyroidism (overactive thyroid) is more likely to cause you to wake up early during the night. This is because excess thyroid hormones can speed up your metabolism and stimulate your nervous system, leading to symptoms like anxiety, rapid heart rate, and restlessness.
This can increase cortisol levels (the stress hormone), which may cause you to wake up earlier than usual, especially in the morning. These factors can disrupt your sleep cycle, causing you to wake up frequently or too early in the morning.
Lisa explained: “Cortisol plays a role in waking you up in the morning, but if your thyroid is overactive, the stress response can become imbalanced, causing you to wake up too early and feel restless.”
Thyroid issues can cause a range of other symptoms. Lisa said: "What distinguishes waking early from thyroid issues from occasional bouts of early morning waking is the presence of other symptoms, such as persistent fatigue, unexplained weight gain or weight loss, and feeling excessively cold or overheating.
“Other symptoms can include irregular periods, brain fog, muscle aches, dry skin, and changes in appetite. Thyroid symptoms usually develop slowly and gradually, and can be quite vague, often overlapping with other conditions, which can make it difficult to diagnose.
If you experience any symptoms, you should speak to your doctor. They may want to conduct a blood test to detect a thyroid problem.