Getting regular, deep sleep is essential to our mental health. While we’re sleeping, our bodies and brains are restoring themselves.
Most adults need between 7 and 9 hours of sleep per night. Many of us, however, are not getting that much. A survey for the Sleep Council showed that in the UK:The Sleep Council. (2013). ‘The Great British Bedtime Report‘. [online] London: The Sleep Council, p.13, p.16, p.25. Available at: https://www.sleepcouncil.org.uk/wp-content/uploads/2013/02/The-Great-British-Bedtime-Report.pdf [accessed 30 Aug. 2017].
- People sleep on average for 6 hours and 35 minutes per night
- A third of those surveyed were sleeping for fewer than 6 hours
- Nearly half said they were too stressed, worried, or low on money to enjoy a good night’s sleep
Contributing factors to sleep problems
There are many reasons why we might be sleeping poorly.
Some of these are easy to understand or control. For instance, we may be going to bed too late, or we may work throughout the night.
As we go through life, we also naturally wake up earlier and earlier. We lose around half an hour of sleep per night with every ten years of age. By our thirties, we have roughly 80% less uninterrupted deep sleep than we did in our teens, and by our fifties, we get almost none.Talbott, S. (2007). The Cortisol Connection. Alameda, CA: Hunter House, p.141.
But there are several other factors that may be affecting our sleep. The most common ones are listed below.
Disruptive environments can cause sleep issues. These might include:
- Sleeping near loud children, pets, or neighbours
- Sleeping in a place with too much ambient light
Our sleep may also be affected by chronological or seasonal changes:NHS Inform. (2017). ‘Seasonal affective disorder’. [online] Available at: https://www.nhsinform.scot/illnesses-and-conditions/mental-health/seasonal-affective-disorder-sad [accessed 16 Nov. 2017].
- A lack of natural sunlight in the day, or too much artificial light at night, can disrupt our circadian rhythms and cortisol production, and lead to sleep problems
- International travel can also disrupt our circadian rhythms (‘jet lag’)
- As the days get shorter in winter, one in three people experience changes in the hypothalamus, which can be severe enough to trigger clinical depression (‘seasonal affective disorder’)
Stress is one of the most obvious and pervasive causes of poor sleep.
When we’re stressed, our brains release hormones such as cortisol and adrenaline. These can disrupt our circadian rhythms, block the production of melatonin and serotonin, and affect our sleep patterns.
Anything which contributes to long-term anxiety can disrupt our sleep, for the same reasons. Some of the most common contributing factors are:
- Difficult interpersonal relationships
- Moving house
- Having problems at work
- Losing a job
Unhealthy lifestyle habits can lead to chronic sleep deficit, which is detrimental to our hormonal balance and mental health. Healthy cortisol levels should:
- Peak in the mornings, after the sun rises
- Gradually start to decline in the late morning, and continue declining through the day
- Prepare the body for melatonin (the ‘sleep hormone’) to be released as the sun goes down
But if our lifestyles are out of step with this natural schedule, because we stay up too late or don’t go to bed, the release of these hormones may be affected.
Another common unhealthy habit is the use of substances such as nicotine, alcohol, and caffeine. These can all have a stimulant effect during the night, and prevent us from getting ‘deep sleep’.Sleep Health Foundation. (2013). ‘Caffeine, food, alcohol, smoking and sleep’. [online] Available at: http://www.sleephealthfoundation.org.au/fact-sheets-a-z/262-caffeine-food-alcohol-smoking-and-sleep.html [accessed 16 Nov. 2017].
There are many ways in which nutritional imbalances can affect our sleep. In particular, they can often cause gut issues.
As well as the use of stimulants (see above), sleep issues may be triggered by:Kittaneh, F. (2015). ‘Don’t snooze on nutrition’. [online] Huffington Post. Available at: https://www.huffingtonpost.com/firas-kittaneh/food-sleep_b_6762920.html [accessed 16 Nov. 2017].Jackson, M.L., Butt, H., Ball, M., Lewis, D.P., Bruck, D. (2015). ‘Sleep quality and the treatment of intestinal microbiota imbalance in chronic fatigue syndrome: a pilot study’. [online] Sleep Science, 8(3), pp.124–133. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4688574/ [accessed 1 Sept. 2017].Alternative Daily. (2015). ‘Parasites and seven other reasons you aren’t sleeping’. [online] Available at: http://www.thealternativedaily.com/reasons-for-insomnia/ [accessed 1 Sept. 2017].
- Deficiencies in calming nutrients, such as magnesium, calcium, zinc, essential fatty acids, and complex carbohydrates
- Imbalances in our blood sugar, which can cause it to rise and fall rapidly
- Parasites in our gut, many are which are most active in the middle of the night
- Intolerances to food (gluten, dairy, eggs, corn, soy, sugar), which can lead to gut inflammation, and also cause our cortisol levels to rise
- A lack of healthy bacteria in our diet, which can lead to gut dysbiosis
Hormonal imbalances can cause a range of sleep issues. They can stop us falling asleep, wake us up during the night, and/or prevent us going back to sleep once we’re awake.
Three common types of hormones affecting our sleep are stress hormones, sex hormones, and thyroid hormones. They can either disrupt our sleep directly, or cause neurotransmitter imbalances that in turn disrupt our sleep.
Stress hormone and neurotransmitter imbalances
High levels of cortisol and adrenaline can make it harder to fall and stay asleep:
- Chronically high levels of stress hormones can lead to HPA axis dysregulation
- High cortisol levels can disrupt our circadian rhythms
High cortisol levels can also stop our brains converting serotonin to melatonin:Kharrazian, D. (2013). Why Isn’t My Brain Working? Carlsbad, CA: Elephant Press, p.306.Pandi-Perumal, S.R., Srinivasan, V., Maestroni, G.J., Cardinali, D.P., Poeggeler, B., Hardeland, R. (2006). ‘Melatonin: Nature’s most versatile biological signal?’ FEBS Journal, [online] 273(13), pp.2813–2838. Available at: https://www.ncbi.nlm.nih.gov/pubmed/16817850 [accessed 30 Aug. 2017].
- While serotonin is associated with wakefulness, it’s needed at the end of the day to trigger melatonin production in the brain’s pineal gland
- Melatonin helps to reduce anxiety and control our sleep cycles
Sex hormone imbalances
A range of sex hormones, in both men and women, can affect our sleep cycles.
In women, estrogen helps to maintain the levels of serotonin receptors in the brain, while both estrogen and progesterone help to promote GABA function. Healthy levels of both serotonin and GABA are needed to keep our sleep patterns stable.
However:Richard, R. (2016). ‘Sex hormones and sleep’. [online] Sanesco. Available at: https://sanescohealth.com/sex-hormones-and-sleep/ [accessed 17 Nov. 2017].
- Estrogen levels decline over a woman’s lifetime, meaning that older women may become prone to serotonin imbalances
- During the menstrual cycle, estrogen and progesterone levels can fluctuate a lot, and the ratio between them can change
- Levels of estrogen and progesterone drop sharply when women go through the menopause
In men, the relationship between sex hormones and sleep is less clear. But testosterone is linked to serotonin production, and it seems that high levels of testosterone can prevent men from sleeping well.Richard, R. (2016). ‘Sex hormones and sleep’. [online] Sanesco. Available at: https://sanescohealth.com/sex-hormones-and-sleep/ [accessed 17 Nov. 2017].
The thyroid gland helps to control the production of almost all our hormones. National Academy of Hypothyroidism. (2017). ‘Can’t sleep? It may be your thyroid!’ [online] NaHis. Available at: https://www.nahypothyroidism.org/cant-sleep-it-may-be-your-thyroid/ [accessed 17 Nov. 2017].
When it malfunctions, usually because of a physical condition, it may produce too many of the thyroid hormones ‘T3’ and ‘T4’. These hormones regulate our levels of serotonin, melatonin, and (in women) estrogen.
If the thyroid hormones are out of balance, the levels of these other hormones may also change erratically, and this can disrupt our sleep.Pereira Jr., J.C., Andersen, M.L. (2014). ‘The role of thyroid hormone in sleep deprivation’. Medical Hypotheses [online], 82(3), pp.350–355. Available at: https://www.ncbi.nlm.nih.gov/pubmed/24468575 [accessed 17 Nov. 2017].
Working night shifts and travelling across time zones disrupt our circadian rhythms, which can lead to temporary or chronic sleep problems.
Possible effects of poor sleep on mental health
Breslau, Roth, Rosenthal and Andreski. Sleep disturbance and psychiatric disorders: A longitudinal epidemiological study of young Adults. Biological Psychiatry. 1996. 39(6), pp. 411-418.
Research shows that our mental and physical issues may become worse if we sleep for fewer than seven hours.The Sleep Council. (2013). ‘The Great British Bedtime Report‘. [online] London: The Sleep Council, p.6. Available at: https://www.sleepcouncil.org.uk/wp-content/uploads/2013/02/The-Great-British-Bedtime-Report.pdf [accessed 30 Aug. 2017].
Over time this can contribute to, or exacerbate, problems including:Amen, D. (2013). Unleash The Power Of The Female Brain. New York, NY: Harmony Books, p.74.Holland, J. (2015). Moody Bitches. New York, NY: Penguin, p.195.Talbott, S. (2007). The Cortisol Connection. Alameda, CA: Hunter House, p.99.
- Poor memory
- Poor attention and concentration
- Mood swings
- Mental breakdown
Below are some of the key effects that sleep issues can have on our bodies, and how they can affect our mental health.
It’s crucial to keep our hormone levels healthy. Hormonal imbalances can contribute to a number of mental health issues.
Changes to stress hormone levels
Getting fewer than seven hours of sleep per night, or losing an hour of our usual sleeping time, can increase our levels of the stress hormone cortisol. High cortisol levels are closely connected to symptoms of anxiety.Talbott, S. (2007). The Cortisol Connection. Alameda, CA: Hunter House, p.34, p.96, p.143.
A lack of sleep leads to a surge of stress hormones in the hippocampus (our memory centre), and missing a single night’s sleep can have a huge impact on cognitive function. Even six hours’ sleep, instead of eight, ‘can cause notable declines in reaction time and performance on standard mental function tests’.Perlmutter, D., Colman, C. (2004). The Better Brain Book. New York, NY: Riverhead Books, p. 129.
Risk of insulin resistance
A lack of sleep can cause low blood sugar levels, and over time this can contribute to the development of insulin resistance. This is a common factor in the development of type 2 diabetes. Mesawrwi, O., Polak, J., Jun, J., Polotsky, V.Y. (2013). ‘Sleep disorders and the development of insulin resistance and obesity’. Endocrinology and Metabolism Clinics of North America, [online] 42(3), pp.617–634. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3767932/ [accessed 17 Nov. 2017].
Reductions in human growth hormone levels
Human growth hormone helps us grow, and to repair tired or damaged body tissue. Our brains mainly produce it during deep sleep. As a result, if our sleep is disrupted, this restorative process may be disrupted too.Tuck. (2017). ‘Sleep and human growth hormone’. [online] Available at: https://www.tuck.com/athletes/ [accessed 17 Nov. 2017].
Reductions in leptin levels
Leptin is the hormone that controls our appetite, body weight, metabolism, and reproductive functions. Its production is reduced by a lack of sleep, which can lead to all of these processes being slowed down or disrupted.Talbott, S. (2007). The Cortisol Connection. Alameda, CA: Hunter House, p.100.
Poor sleep can disrupt our neurotransmitter balance, affecting our levels of serotonin and melatonin. This can contribute to anxiety and feelings of panic.Scott, T., Tatta, J. (2015). ‘Nutritional influences on anxiety and musculoskeletal pain. [online] The Anxiety Summit. Available at: http://season3.theanxietysummit.com/ [accessed 17 Nov. 2017].
A lack of sleep can also cause imbalances in our dopamine levels. Low levels of dopamine can contribute to low concentration and attention, as well as depression, while high levels of dopamine can contribute to agitation and paranoia.Smith, F. (2017). ‘Dopamine and insomnia’. [online] Livestrong. Available at: https://www.livestrong.com/article/488137-dopamine-insomnia/ [accessed 17 Nov. 2017].
Chronic lack of sleep can cause:Peters, B.R. (2013). ‘Not quite enough: the consequences of sleep deprivation’. [online] Huffington Post. Available at: https://www.huffingtonpost.com/stanford-center-for-sleep-sciences-and-medicine/sleep-deprivation_b_3536674.html [accessed 17 Nov. 2017].Reasoner, J. (2017). ‘Leaky gut syndrome in plain english – and how to fix it’. [online] SCD Lifestyle. Available at: http://scdlifestyle.com/2010/03/the-scd-diet-and-leaky-gut-syndrome/ [accessed 26 Oct. 2017].Alternative Daily. (2015). ‘Parasites and seven other reasons you aren’t sleeping’. [online] Available at: http://www.thealternativedaily.com/reasons-for-insomnia/ [accessed 1 Sept. 2017].
- Stomach pains and poor digestion
- Gut dysbiosis, where the levels of healthy and unhealthy bacteria in our gut are out of balance
- Leaky gut, a condition where the gut becomes more porous, resulting in our blood absorbing large, undigested food molecules, and other harmful things such as yeasts and toxins
Inflammation is our bodies’ normal response to damage, or infection by viruses or bacteria.
A lack of sleep can prompt our immune systems to turn against healthy tissue and organs. In fact, according to recent research, losing sleep for even part of one night can trigger tissue-damaging inflammation.ScienceDaily. (2008). ‘Loss of sleep, even for a single night, increases inflammation in the body’. [online] ScienceDaily. Available at: www.sciencedaily.com/releases/2008/09/080902075211.htm [accessed 30 Aug. 2017].
Inflammation has been linked to mental health issues such as depression. It’s important to note that research into this connection is young, but there is a strong correlation between the two. What’s unclear is whether inflammation contributes more to sleep issues, or vice-versa.Mullington, J.M., Simpson, N.S., Meier-Ewert, H.K., Haack, M. (2010). ‘Sleep loss and inflammation’. Best Practice and Reseach: Clinical Endocrinology and Metabolism, [online] 24(5), pp.775–784. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3548567/ [accessed 17 Nov. 2017].Berk, M., Williams, L.J., Jacka, F.N., O’Neil, A., Pasco, J.A., Moylan, S., Allen, N.B., Stuart, A.L., Hayley, A.C., Byrne, M.L., Maes, M. (2013). ‘So depression is an inflammatory disease, but where does the inflammation come from?’ BMC Medicine, [online] 11, p.200. Available at: https://bmcmedicine.biomedcentral.com/articles/10.1186/1741-7015-11-200 [accessed 30 Aug. 2017].Heffner, K.L., Ng, H.M., Suhr, J.A., France, C.R., Marshall, G. D., Pigeon, W.R., Moynihan, J.A. (2012). ‘Sleep disturbance and older adults’ inflammatory responses to acute stress’. American Journal of Geriatric Psychiatry, 20(9), pp. 744–752.Alban, D. (2017). ‘Brain inflammation may be the cause of your depression’. [online] Be Brain Fit. Available at: http://bebrainfit.com/brain-inflammation-depression/ [accessed 30 Aug. 2017].
Poor sleep, mental health, and their reciprocal relationship
As we can see, there are more than a few similarities between ‘possible factors’ and ‘possible effects’. This is because the causes and effects of poor sleep may be difficult to separate. Often, they feed into each other.
So, for instance, high levels of cortisol can contribute to insomnia, and poor sleep can trigger the production of cortisol too.
Or, to take another example, gut dysbiosis can disrupt our sleep, and a lack of sleep can also increase gut dysbiosis.Servan-Schreiber, D. (2005). Healing Without Freud or Prozac. London: Rodale, p. 111.
It’s important to get the advice of a healthcare professional, when trying to understand whether our sleep issues are a contributor to our mental health issues, or an effect of them.