In this article:
- What is the circadian rhythm?
- What can disrupt the sleep-wake cycle?
- How the thyroid affects your sleep
- Treating your thyroid can treat your fatigue
- How to maintain a healthy sleep-wake cycle
Our understanding of sleep's importance is ever-expanding as our population runs on fewer and fewer hours of sleep. With our consistently elevated stress levels, busy schedules, and alarmingly high anxiety rates, our need for prioritizing sleep is at an all-time high. Yet, despite our cultural penchant for prioritizing productivity over sleep, research shows that poor sleep habits are adversely affecting our physical and mental health. However, our habits are not the only factors that affect sleep. Health conditions like thyroid disease can also interfere with our ability to get a good night's rest.
What is the circadian rhythm?
The circadian rhythm is a 24-hour cycle or clock that our bodies follow. It is regulated by the suprachiasmatic nucleus (SCN) in the hypothalamus of the brain and controls our sleep-wake cycle. Sometimes, we refer to the SCN as our "master clock."
The master clock is influenced primarily by environmental stimuli—especially light. This is why we tend to feel sleepy when light wanes in the evening and often feel awake when the sun rises. Other factors that can influence the master clock include exercise, socialization, eating habits, and temperature.
Many different systems in our bodies follow the master clock, using it to guide when our organs perform specific functions. For example, the circadian rhythm helps dictate when digestive proteins are made based on the typical eating times. It also helps regulate hormone secretion for energy expenditure.
What can disrupt the sleep-wake cycle?
Numerous factors and situations can disrupt the delicate balance of our sleep-wake cycle. Because sleep is vital for healing, disease prevention, enhancing cognitive function, and memory formation, it is imperative to identify and manage factors that disrupt your sleep.
The sleep-wake cycle can be interrupted by:
- Jet lag
- Working nights
- Irregular sleep patterns
- Physical and mental health conditions (including obstructive sleep apnea and anxiety)
- Lack of access to natural light (such as being blind or working in a place without adequate lighting)
How the thyroid affects your sleep
Most people refer to the circadian rhythm when it comes to regulating the sleep-wake cycle. Indeed, sleep regulation is one of the most prominent examples of the circadian rhythm in action. To control the sleep-wake cycle, the master clock uses light to determine when to feel alert and when to feel tired. The suprachiasmatic nuclei (SCN) generates the circadian rhythm of many hormones, like melatonin, produced in the pineal gland, that directs us to fall and stay asleep.
The SCN also controls the rhythm of other hormones, including thyrotropin, produced in the pituitary gland, which stimulates the thyroid to release thyroid hormones. When you have an underactive or overactive thyroid, it can affect thyrotropin production and even your circadian rhythm.
People with hyperthyroidism struggle to get a good night's rest because excess thyroid hormones can cause nervousness, irritability, increased urination, and night sweats.
On the contrary, people who have hypothyroidism often struggle with feeling cold at night and muscle and joint pain, making it difficult to get comfortable. Sometimes, hypothyroidism can lead to hypersomnia, where you need to sleep throughout the day.
Additionally, hypoventilation during sleep (as in not breathing enough per minute while you are sleeping) can lead to further feelings of tiredness throughout the day. Hypoventilation may even cause chronic health problems like heart conditions.
Finally, people with thyroid disease can suffer from restless leg syndrome (RLS), characterized by unpleasant sensations in the legs during rest. Regrettably, RLS often starts at night and prevents you from getting a good night's rest.
Test and treat hypothyroidism to alleviate fatigue
Feeling fatigued is a hallmark symptom of most diseases, including thyroid disease. If you experience fatigue, consider taking a thyroid blood test to understand how your thyroid functions. Many labs only look at thyroid-stimulating hormone (TSH). TSH is a hormone produced in the brain that stimulates the thyroid gland to produce the thyroid hormones: thyroxine (T4) and triiodothyronine (T3).
It's also critical to measure fT3, fT4, and TPO antibodies (antibodies that mistakenly attack healthy thyroid tissue) to understand the full picture of your thyroid health.
Should your results show that your thyroid is underactive, it is easily treatable in almost everyone. Optimizing your thyroid levels with thyroid hormone replacement medication is usually the first step in minimizing symptoms. When choosing thyroid medication with your thyroid doctor, remember that there is no one-size-fits-all treatment.
Once you start taking thyroid medication, it can take some time to titrate to the appropriate dose for you. However, when you reach your ideal dosage, you can expect to see improvements in many of your thyroid symptoms, including your ability to get a better night's rest and decreased daytime fatigue.
Creating balance in your thyroid hormones can restore your sleep-wake cycle.
How to maintain a healthy sleep-wake cycle
Our sleep-wake cycle is sometimes out of our control. However, there are many steps we can take each day to optimize this critical function in our bodies.
Follow a regular sleep schedule.
Bedtime is not just for children; adults need a bedtime too. Being consistent in when you go to bed and wake up can help regulate your circadian rhythm.
Exercise every day.
Being physically active during daylight makes it easier to fall asleep when darkness falls.
Be in the sun.
Natural light is one of the primary stimuli that regulate the sleep-wake cycle. Most people are getting less sun than those in generations past, so it is important to prioritize getting sunshine each day.
Limit stimulants (a.k.a. caffeine).
Drinking caffeinated beverages after mid-day can make it hard for your brain to shut off. Therefore, limit caffeinated drinks to early in the day, or switch to a delicious caffeine-free alternative.
A note from Paloma Health
If you are struggling with fatigue or feel that you cannot get a good night's rest, test your thyroid hormone levels to determine your thyroid function and if there is a need for further evaluation with a thyroid doctor.