How does stress impact sleep?
Woe is me!
Recently, while I was contemplating the importance of good sleep, I realized that my sleeping issues have been with me since childhood. I always thought they emerged in adulthood but I clearly remember, as a child, lying awake at night listening to the melodic snoring of my younger sister. I would create stories in my mind to keep me entertained while I waited for sleep to come.
In high school, I would pass the time reading my favourite books like Harry Potter. I would read until my eyes hurt and my vision became blurry. In high school, though, the late nights, early morning and increased workload started to cause issues. It would take every ounce of will power to get out of bed and ready for school. As soon as the bus would appear I would shuffle into the window seat and sleep the 1-hour long bus ride to school. My sister would sit next to me, like a bodyguard, making sure no one woke me.
Unfortunately, this pattern wasn’t a transient “teenager thing”. It has persisted throughout most of my life; through university and even into my post-graduate studies at the Canadian College of Naturopathic Medicine.
Try as I may, I would continuously fail at falling asleep earlier and fail at waking up on time. I so desperately wanted a well-paced morning routine, where I could exercise, meditate and get ready for my day. Although not as frequent anymore, there are still nights where I lie wide awake and mornings where it’s a real struggle to get out of bed.
I know I’m not the only one who has experienced this pattern. I hear similar stories from my patients all the time. They, just like me, want to start their day “right” and not feel rushed from the moment they get out of bed.
Delayed sleep phase disorder
The pattern I’ve described above, the inability to fall asleep at the desired time and the inability to wake up at the desired time, also known as delayed sleep phase disorder, is the most common circadian rhythm sleeping disorder (CRSD). It is estimated that 0.17% of the general population and 7-16% of teenagers struggle with delayed sleep phase disorder (1).
Delayed sleep phase disorder is only one of the many different dysfunctional sleeping patterns that exist. Some have difficulties with :
- Staying asleep during the night.
- Falling asleep at night.
- Waking up on time regardless of the number of hours slept.
- Early waking with the inability to fall back asleep.
- Staying awake during the day or early evening.
In this blog, we will discuss how dysfunction in our biological clock (circadian rhythm) can impact our sleeping and waking cycles. There are many causes for sleep dysregulation and if you are experiencing issues with your sleep, consult your medical doctor and/or naturopathic doctor.
The biology of our biological clock
As mentioned above our biological clock is known as the circadian rhythm and ALL living organisms exhibit circadian rhythmicity. Our biological clock is located in the suprachiasmatic nucleus which is a tiny region of the brain.
Virtually every biological and behavioural aspect of our being follows a 24-hour clock (1). For example, our biological clock lets us know when it is time to eat, drink, sleep and wake-up. It also regulates our body temperature and neurohormones (e.g. cortisol and melatonin) all depending on where we are in our 24-hour clock (2).
Circadian rhythm sleeping disorders emerge when our internal 24-hour biological clock does not match the 24-hour rhythm of the external environment. There are a few different factors that can contribute to these misalignments, however, we will focus on how stress and cortisol impact your biological clock and sleeping patterns.
What is cortisol?
Cortisol, also known as the stress hormone is the main hormone secreted by the adrenal gland cortex. The adrenals are two little glands located on top of your kidneys. The hormone cortisol is continuously being secreted, however, the amounts secreted depend on our circadian rhythm and level of stress.
Cortisol and the circadian rhythm
Let’s take a look at how the circadian rhythm controls cortisol production. We produce the most cortisol first thing in the morning. It is said that this surge in cortisol is what wakes us up naturally in the morning. As the day progresses, we produce less and less cortisol.
We produce the lowest amounts of cortisol during the first half of our sleep cycle. As morning approaches (second half of our sleep cycle), cortisol production ramps up in order to wake us up naturally at the appropriate time; which is generally thought to be around 8 am for most people.
Cortisol and sleep
When we experience physical, mental and/or emotional stress cortisol is secreted and our fight or flight response is activated. As the name suggests, the fight or flight response prepares our body to either fight or flee. Our heart rate increases, blood is pumped preferably to the muscles of our arms and legs, our heart dilates and our liver starts to produce glucose in order to provide energy for muscle contraction (3).
The issue, however, is that “most stressors we experience in twenty-first-century life do not require the “fight or flight” response, yet our bodies haven’t adapted as our environment has changed. Our stress response may be triggered by an endless number of situations – overwork, environmental pollution, emotional factors, worry and so on” (4).
Unfortunately, studies have shown that exposure to prolonged stress can significantly decrease morning cortisol (6) which could impact a person’s ability to wake up in the morning feeling refreshed and rested.
Prolonged stress can also cause elevated cortisol in the evening. As a result, individuals could experience difficulties with falling asleep (7).
Lastly, prolonged stress can also increase cortisol levels during the first half of the sleep cycle (8). This could cause people to wake up frequently during the night and even prevent them from falling back asleep.
Now, cortisol isn’t all bad, in fact we actually need cortisol to live. “Animals whose adrenal glands have been removed die if exposed to any significant environmental stress” (5).
The wrap up
As you can see, stress, especially exposure to long term stress can negatively impact our circadian rhythm. Disruption in our circadian rhythm can, in turn, impact the body’s ability to regulate our waking and sleeping patterns AND affect many other aspects of our health such our brain, heart, digestion, and metabolism (1).
Stay tuned for part 2 of the series where we will discuss the importance of good sleep hygiene
Disclaimer
The information presented in this blog is NOT intended to prevent, diagnose or treat any disease. The suggestions and ideas presented are for information only and should NOT be interpreted as medical advice. The information in this document does NOT replace the services or instructions of a medical doctor or naturopathic doctor. Please consult your health care provider before beginning any new protocols.
Resources
- Neurol Clin. 2012 November; 30(4): 1167–1191. https://doi:10.1016/j.ncl.2012.08.011
- Recent Prog Horm Res. 1999;54:33-58; discussion 58-9.
- Unglaub Silverthorn, Dee. “Endocrine Control of Growth and Metabolism.” Human Physiology: An Integrated Approach. San Francisco, Benjamin Cummings, 2010. page 386
- Lewis, Randine. “The Infertility Cure: The Ancient Chinese Wellness Program for Getting Pregnant and Having Healthy Babies.” Step Three: Clearing Your Energy with Acupuncture and Acupressure. New York, 2004. page 86
- Unglaub Silverthorn, Dee. “Endocrine Control of Growth and Metabolism.” Human Physiology: An Integrated Approach. San Francisco, Benjamin Cummings, 2010. pages 758-761
- Shuhei Izawa, Keisuke Saito, Kentaro Shirotsuki, Nagisa Sugaya, Shinobu Nomura, Effects of prolonged stress on salivary cortisol and dehydroepiandrosterone: A study of a two-week teaching practice, Psychoneuroendocrinology, Volume 37, Issue 6, 2012, Pages 852-858, ISSN 0306-4530, https://doi.org/10.1016/j.psyneuen.2011.10.001.
- Rystedt, L. W., Cropley, M., Devereux, J. J., & Michalianou, G. (2008). The relationship between long-term job strain and morning and evening saliva cortisol secretion among white-collar workers. Journal of Occupational Health Psychology, 13(2), 105–113. https://doi.org/10.1037/1076-8998.13.2.105
- W. Kern, B. Perras, R. Wodick, H. L. Fehm, and J. Born, Hormonal secretion during nighttime sleep indicating stress of daytime exercise, Journal of Applied Physiology, Vol. 79, No. 5, https://doi.org/10.1152/jappl.1995.79.5.1461. 01 NOV 1995
by Dr Eric Viegas, ND
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