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Getting enough sleep is a vital component of a healthy lifestyle, but it tends to be overlooked. Our body needs sleep to function properly.
That explains why sleep-deprived persons are always tired, experience decreased productivity at work, and suffer many other consequences due to the lack of good night’s rest.
Since lack of sleep and insomnia affect different aspects of our health we have to wonder whether there is any connection with thyroid.
Do thyroid and insomnia influence one another in any way? Scroll down to find out.
Insomnia is defined as the inability or difficulty to fall asleep or staying asleep even when a person has a chance to do so.
Not all cases are the same which is why we can categorize insomnia to acute and chronic, according to the National Sleep Foundation[i].
Acute insomnia is brief, and it usually occurs due to some life circumstances such as receiving bad news or being nervous because you have an important meeting/exam the next morning.
Most of us have experienced acute insomnia at one point or another and it goes away on its own, without any treatment whatsoever.
Chronic insomnia is entirely different from its counterpart and it refers to cases when a person experiences disrupted sleep at least three nights a week for at least three months.
Causes of chronic insomnia go deeper than nervousness before the exam, they can stem from hormonal imbalances, medical conditions, psychological issues, and many other factors.
Chronic insomnia usually requires a treatment in the form of sleep aids prescribed by doctor or treatment of an underlying health problem that led to insomnia.
How common is insomnia?
According to the American Sleep Association, about 50-70 million US adults have a sleep disorder with insomnia being the most prevalent specific sleep disturbance.
About 30% people have acute while 10% are affected by chronic insomnia.
About 37% of adults 20-39 years old report short sleep duration while 40% of the population aged 40-59 report the same.
In addition, about 35.3% of adults report less than seven hours of sleep during a 24-hour period[ii].
The CDC reports that 1 in 3 American adults don’t get “enough sleep on a regular basis. Sleeping less than seven hours a day” is strongly associated with an increased risk of developing obesity, diabetes, hypertension (high blood pressure), stroke, heart disease, and mental distress[iii].
Thyroid and sleep deprivation
Sleep is essential for good health, just like a well-balanced diet and regular physical activity.
When we don’t get enough good night’s rest the effects show on our body, including thyroid function.
What most people don’t know is that sleep and thyroid are connected. Let’s see how.
TSH and thyroid hormones have circadian rhythm
Circadian rhythm is a 24-hour cycle in any physiological processes of humans, animals, and plants. While endogenously generated, circadian rhythm can be influenced by a number of external factors.
It is a little-known fact that TSH (thyroid-stimulating hormone) and thyroid hormones have their circadian rhythm.
Lucke C. et al found that TSH peaks from 8pm to 2am while nadir or the lowest point is from 7am to 2pm.
While thyroxine (T4) exhibits peak values from 8am to 12am and lowest points from 11pm to 3am.
Peak values of triiodothyronine are from 7am to 1pm while nadir is from 11pm to 3am[iv].
On the other hand, Russell W. et al report that TSH levels are at their highest point between 2am and 4am while their lowest point is between 4pm and 8pm. Free T3 shows a significant circadian rhythm, but to a lesser extent than TSH, scientists explain.
Taking into consideration circadian rhythms of thyroid hormones could be a valuable method of getting the most out of hormone replacement[v].
Although more research on this topic is necessary in order to find out more about circadian rhythm of thyroid hormones, the current evidence shows that they could be related to the quality of sleep.
Since healthy circadian rhythm requires getting enough sleep (as it regulates sleep-wake cycle), this could mean that insomnia could alter the circadian rhythm of thyroid hormones and impair the gland’s efficacy.
Cortisol is a hormone your body releases in response to stress. The hormone is produced by adrenal glands which are two tiny glands located on top of the kidneys.
While it is considered a “stress hormone”, cortisol also participates in the breakdown of lipids, carbohydrates, and proteins. Stress has a major influence on our physical and psychological health including thyroid function.
Walter K.N. at al evaluated the relationship between serum TSH and cortisol levels in young men and women without clinical evidence of hypothyroidism. They found that TSH is strongly connected to cortisol levels.
These results only confirm the theory that hypothyroid patients have high cortisol levels, too.
It’s simple; hypothyroid persons have high TSH levels and insufficient levels of T3 and T4. The potential explanation for the positive TSH-cortisol relationship is that hypothyroidism, both clinical and subclinical, is linked to subtle metabolic stress[vi].
In case of hypothyroidism (when levels of TSH are elevated) cortisol is higher too, but in a setting where primarily cortisol levels are high, the suppression of TSH is observed. Basically, high TSH also lead to increase in cortisol.
More stress or rise in cortisol can deplete levels of TSH.
Why is cortisol important? Increasing cortisol or prolonged stress lessens the length and quality of sleep. In fact, Morin C.M. et al discovered that stress is a risk factor for insomnia. Insomniacs perceived their lives as more stressful than their counterparts[vii].
To sum up, cortisol is strongly linked with thyroid hormone levels and, if stress left unresolved it can create sleep disturbances.
Estrogen and progesterone imbalance
In previous articles, we have evaluated the relationship between estrogen and progesterone. Estrogen has its receptors in thyroid[viii] and levels of this hormone have a huge influence on thyroid function.
This could explain why women are more prone to thyroid disorders than men.
Estrogen dominance is linked to hypothyroidism, both conditions have similar symptoms too.
On the other hand, progesterone deficiency is common among patients with polycystic ovary syndrome. The low or insufficient concentration of this hormone induces estrogen dominance.
Not only do estrogen and progesterone play a role in thyroid function, but they also influence sleep quality. Impaired levels of these hormones could also contribute to insomnia, Jehan et al found.
Plus, progesterone has “respiratory stimulant properties and it maintains the tone of genioglossus muscles, in postmenopausal women the lack of this hormone increases the risk of sleep apnea which causes additional sleep problems.”[ix]
Melatonin is a hormone produced by the pineal gland in the brain and its primary function is to regulate sleep-wake cycles. Wright M.L. et al found that high concentration of melatonin exhibits an inhibitory effect to the thyroidal response to TSH[x].
Interestingly, Garcia-Marin R. et al discovered that key enzymes for biosynthesis of melatonin (AANAT and ASMT) are regulated by TSH.
The same study revealed that thyroid C-cells synthesize melatonin under TSH control and provides more evidence to theories that melatonin is involved in thyroid function by directly regulating thyroglobulin gene expression in follicular cells[xi].
Bearing in mind that melatonin regulates sleep and wake cycles while TSH controls enzymes involved in the synthesis of this hormone we can conclude that impaired thyroid function (especially in TSH concentration) can disturb one’s circadian rhythm through this mechanism as well.
The relationship of thyroid and insomnia is deeper than we think. Impaired thyroid function can contribute to insomnia through fatigue and depression too.
Evidence shows that patients with hypothyroidism exhibit poorer mental health that commonly manifests itself as depression. That said, hyperthyroid individuals can also suffer from both depression and anxiety[xii].
A study carried out by Nutt D. et al revealed that 83% of depression patients had at least one insomnia symptom, compared to 36% of adults who didn’t have depression.
The relationship between the two is so strong that sleep disorders, primarily insomnia, are considered core symptoms of depression[xiii]. Basically, the study showed that depression and insomnia tend to go hand in hand.
Since millions of people have depression and thyroid disorders, the influence of thyroid function becomes even more evident.
Heart palpitations are sensations that make you feel like you’re having hard, rapid, irregular heartbeats or a combination of them all. Palpitations are very common in persons with hyperthyroidism[xiv].
Why does this happen?
Changes in heart rate stem from a change in the nervous system’s control of the heart.
Due to the excessive levels of thyroid hormones in the body, it is not uncommon for heart rate to reach 90 beats per minute (tachycardia) or even higher. Plus, the amount of blood pumped out by heart is a common occurrence in hyperthyroidism and it can contribute to palpitations as well.
Heart palpitations make a hyperthyroid person wake up frequently at night. As a result, the affected individual doesn’t get enough sleep. While this won’t do much harm when happens occasionally, it can contribute to insomnia and sleep deprivation in the long run, especially if left unresolved.
Getting enough sleep
Sleep deprivation depletes energy levels, decreases productivity, negative affects cognitive functions, and it exhibits many other negative effects on our overall health and wellbeing.
Thyroid function is strongly associated with our sleep and wake cycle, but even if you have some thyroid-related disorder you can still get much-needed good night’s rest.
Below, you can see different ways to relieve insomnia and sleep better:
- Consult your doctor – the first, and most important, the thing to do is to consult your doctor about sleep irregularities, particularly if they happen on a regular basis. Your physician will inform you about different things you can do to improve quality of sleep or, if insomnia is involved, they may prescribe medications that won’t disturb thyroid function
- Stay active – regular physical activity is vital because it helps manage stress (remember, cortisol is deeply involved in insomnia). While physical activity is important, strive to avoid over-exercising because it could raise your cortisol. Getting 30 minutes of activity a day is enough. Exercise in the morning and meditate or do yoga at night
- Take your thyroid medications at night – remember, thyroid hormones are at their highest during the night so you should ask your doctor whether it’s okay to take thyroid hormone pills in the evening
- Have a regular sleep schedule – go to bed every night at the same time and set the alarm to wake up every morning at the same time as well
- Make some changes in your environment – your bedroom should be calming and peaceful, without too much clutter and noise
- Quit smoking – nicotine is a stimulant which is why it takes longer for smokers to fall asleep
Most of us experience insomnia, either acute or chronic, and it shows on our physical and psychological health.
Insomnia and thyroid function are strongly related, although that’s not something that comes to our mind when we’re trying to uncover the root cause behind the inability to fall asleep.
If you have some thyroid disorder and experience sleep-related difficulties, consult your doctor about the best way to manage this problem.
[i] Insomnia, National Sleep Foundation https://sleepfoundation.org/insomnia/content/what-is-insomnia
[ii] Sleep and sleep disorder statistics, American Sleep Association https://www.sleepassociation.org/sleep/sleep-statistics/
[iii] 1 in 3 adults don’t get enough sleep, CDC https://www.cdc.gov/media/releases/2016/p0215-enough-sleep.html
[iv] Lucke C, Hehremann R, von Mayersbach K, von zur Muhlen A. Studies on circadian variations of plasma TSH, thyroxine and triiodothyronine in man. Acta Endicronologica 1977 Sep;86(1):81-8 https://www.ncbi.nlm.nih.gov/pubmed/578614
[v] Russell W, Harrison RF, Smith N, et al. Free triiodothyronine has a distinct circadian rhythm that is delayed but parallels thyrotropin levels. Journal of Clinical and Endocrinology Metabolism 2008 Jun;93(6):2300-6. Doi: 10.1210/jc.2007-2654 https://academic.oup.com/jcem/article/93/6/2300/2598837#52609844
[vi] Walter KN, Corwin EJ, Ulbrecht J, et al. Elevated thyroid stimulating hormone is associated with elevated cortisol in healthy young men and women. Thyroid Research. 2012;5:13. doi:10.1186/1756-6614-5-13. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3520819/
[viii] Santin AP, Furlanetto TW. Role of Estrogen in Thyroid Function and Growth Regulation. Journal of Thyroid Research. 2011;2011:875125. doi:10.4061/2011/875125. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3113168/
[ix] Jehan S, Masters-Isarilov A, Salifu I, et al. Sleep Disorders in Postmenopausal Women. Journal of sleep disorders & therapy. 2015;4(5):1000212. doi:10.4172/2167-0277.1000212. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4621258/
[x] Wright ML, Pikula A, Babaski AM, et al. Effect of melatonin on the response of the thyroid to thyrotropin stimulation in vivo. General and Comparative Endocrinology 1997 Nov;108(2):298-305. Doi: 10.1006/gcen.1997.6979 https://www.ncbi.nlm.nih.gov/pubmed/9356225
[xi] Garcia-Marin R, Fernandez-Santos JM, Morillo-Bernal J, et al. Melatonin in the thyroid gland: regulation by thyroid-stimulating hormone and role in thyroglobulin gene expression. Journal of Physiology and Pharmacology 2015 Oct;66(5):643-52 https://www.ncbi.nlm.nih.gov/pubmed/26579570
[xii] Hage MP, Azar ST. The Link between Thyroid Function and Depression. Journal of Thyroid Research. 2012;2012:590648. doi:10.1155/2012/590648. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3246784/
[xiii] Nutt D, Wilson S, Paterson L. Sleep disorders as core symptoms of depression. Dialogues in Clinical Neuroscience. 2008;10(3):329-336. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3181883/
[xiv] Ertek S, Cicero AF. Hyperthyroidism and cardiovascular complications: a narrative review on the basis of pathophysiology. Archives of Medical Science : AMS. 2013;9(5):944-952. doi:10.5114/aoms.2013.38685. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3832836/