Understand and Work with Your Circadian Rhythm and Sleep Cycle
A circadian rhythm or cycle is a natural internal process governing a person’s physical, mental, and behavioral changes and is most especially known for regulating the sleep-wake cycle. These natural processes respond primarily to light and dark and affect most living things, including animals, plants, and microbes. Anyone, depending on lifestyle and/or physiology, can be affected by a disruption to their circadian rhythm with the very real potential to negatively affect health but women in menopausal transition and after can be particularly affected. This is because estrogen, progesterone, and other reproductive hormones influence sleep and circadian rhythms. When these hormones are out-of-balance as they so often are in menopausal women, the circadian cycle and sleep will also become irregular with the potential to cause a cascade of other health conditions if not addressed.
“It is a clearly established fact that sex hormones influence sleep and circadian rhythms…” —Hrayr P. Attarian, MD in Sleep Disorders in Women: From Menarche Through Pregnancy to Menopause: A Guide for Practical Management
Many women in menopausal transition often hear from their cohorts that now they’ve begun to experience the symptoms of menopause they’ll probably never sleep well again. Mature women don’t need to feel condemned to insomnia or trouble sleeping.
Many symptoms of menopause including insomnia catch us unaware. After all, we’ve lived all our lives to this point only having to deal with premenstrual symptoms. Many of us have given birth and we know our bodies to be one way. We’ve gotten used to it. So when symptoms of menopause start to occur, we often get caught unaware and the true cause of our symptoms related to menopause don’t even dawn on us. Menopause is new to us and we are not yet aware enough to realize that the enormous hormonal fluctuations occurring within our bodies are often the very causes of symptoms we’d normally ascribe to something else.
With knowledge and understanding of our bodies and how they function during the phases they move through, we can optimize our sleep process. Many women think there is something wrong with their brains for them to have endure insomnia during this time. But that’s wrong and those kinds of thoughts will actually perpetuate insomnia.
The good news is that most women can naturally restore their rhythmic sleep cycle without the need for prescription sleeping pills. Awareness and knowledge combined with simple lifestyle adjustments are key.
“Sleep is a dynamic, fluid process that is tightly connected to our body rhythms and our environment. This process of sleep rejuvenates our energy and also helps to heal the body by supporting the immune system, enhancing memory, improving cognitive function and getting rid of the toxic proteins that are harmful to our brains.” —Maria Sunseri, MD in Sleep After Menopause
Chronobiology, the study of circadian rhythms, is a young scientific discipline which deals with research of the biological clocks and its implications in clinical medicine. It has determined that circadian rhythm disorders are manifest mainly as inappropriate sleep-wake timing, insomnia or excessive sleepiness at inappropriate times. Treatment of circadian rhythm disorders with the use of sleeping pills or wake-promoting agents and without taking chronobiological considerations into account may be futile or even detrimental to a woman’s well-being.
How the Circadian Clock Works
Biological clocks are composed of specific protein molecules that interact with cells throughout the body. Nearly every tissue and organ contains biological clocks. But a master clock or circadian pacemaker in the brain coordinates all the biological clocks in a living thing, keeping them all in sync..
In humans, the master clock is a group of about 20,000 nerve cells or neurons that form a structure called the suprachiasmatic nucleus(1) or SCN. The SCN is found in a part of the brain called the hypothalamus(2) and receives direct input from the eyes.
The SCN controls the production of melatonin, a ubiquitous natural neurotransmitter-like hormonal compound secreted by the pineal gland in the brain which makes you sleepy but which also does so much more.
Melatonin is largely associated with sleep. It is also known for regulating the reproductive cycle. But what most people don’t realize is that melatonin is produced naturally in the cells of the GI tract helping the body to regulate the production of gastric acids and control the lower esophageal sphincter.
The SCN receives information about incoming light from the optic nerves which in turn relay information from the eyes to the brain. When there is less light such as at night, the SCN tells the brain to make more melatonin so you get drowsy. This same melatonin would also find its way to your gastrointestinal tract for other digestive purposes.
Changes in our body along with environmental factors can cause our circadian rhythms and the natural light-dark cycle to be out of sync. If your lifestyle involves artificial and/or LED light in the evenings, there’s too much light and the SCN won’t be telling your brain to make more melatonin. Not only will your sleep be adversely affected but your digestion will, too (eventually causing acid reflux or worse), since melatonin is required to line the intestines so gastric acids will be produced in a regulated balanced way.
More on the Circadian Master ClockThe circadian master clock undergoes significant changes throughout one’s lifespan at both the physiological and molecular levels.
This cyclical physiological process, which is very complex and comprised of many factors may be associated with things like metabolic changes (weight gain or loss), atherosclerosis, impaired cognition, mood disturbances and even the development of cancer.
The way this process works is reflected differently according to whether one is male or female and the well-known sleep disturbances associated with menopause in women are a good example.
Circadian rhythm is detected in the daily pattern of hot flushes with a peak in the afternoons. Melatonin secretions decrease with age in both genders, but in menopausal women there is usually a significant reduction of melatonin levels thereby affecting sleep.
In addition to our sleep, circadian rhythms can influence other very important functions in our bodies:
• hormone release
• eating habits and digestion (see the paragraphs above on melatonin requirements for the gastrointestinal system)
• body temperature
Disturbed sleep and insomnia caused by an erratic circadian rhythm can be caused by:
• jet lag or shift work causing changes in the light-dark cycle
• light from electronic devices at night can confuse our biological clocks
• poor diet that does not include melatonin-rich foods
• lack of moderate natural sunlight
These factors can cause sleep disorders, and may lead to other chronic health conditions, such as obesity, diabetes, digestive disorders, depression, bipolar disorder, and seasonal affective disorder.
Physiological changes that occur during the menopausal transition and after into post-menopause can sometimes have profound effects on sleep quality, daytime functioning and thus quality of life.
Insomnia is reported in about 46% of menopausal women. Research shows that hormone replacement therapy (HRT) in the short-term can be beneficial for improving sleep quality in menopausal women experiencing insomnia or sleep disruption.
Surveys show that more than 80% of working women complain of fatigue with half of them not getting adequate sleep every night. Shift-working postmenopausal women have altered sleep and circadian rhythms which puts them at increased risk for insomnia.
In addition, most mature women who work outside the home return home only to be the principle caregivers for children, home and elderly family members. These responsibilities create an additional burden of stress which increases a woman’s risk for sleep deprivation.
Here are some lifestyle adjustments you can make to help reestablish your healthy circadian rhythm and, as a result, elevate your health and well-being:
• Turn off electronic devices in the evening; make your house and bedroom dark; if you must watch television or look at a screen, be sure it’s at least six feet away;
• Get about a half hour of sunlight every day;
• Eat melatonin rich foods like tart cherries, pistachios, almonds, figs, oats and sweet potatoes; fish like salmon and sardines are also good and so are eggs and milk;
• Perhaps take with a quality melatonin supplement but don’t overdo it; consult with your healthcare practitioner to help you determine how much to take; supplementing with melatonin has been proven to be effective in the treatment of insomnia associated with circadian rhythm abnormalities.
1. Suprachiasmatic nucleus: each of a pair of small nuclei in the hypothalamus(2) of the brain, above the optic chiasma (the X-shaped structure formed at the point below the brain where the two optic nerves cross over each other), thought to be concerned with the regulation of physiological circadian rhythms.
2. The hypothalamus is a region of the forebrain below the thalamus which coordinates both the autonomic nervous system and the activity of the pituitary, controlling body temperature, thirst, hunger, and other homeostatic systems, and involved in sleep and emotional activity.
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• Sleep Disorders in Women: From Menarche Through Pregnancy to Menopause: A Guide for Practical Management. Netherlands, Humana Press, 2006.
• Sunseri, Maria, and Sunseri, Faasm Maria J. Sleep After Menopause: 2nd Edition. N.p., Independently Published, 2015.