Poor sleep

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].

Thyroid imbalances

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.

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. Mesarwi, 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].