The Science of Sleep: Functional Medicine for Restorative Sleep

Restorative regular sleep is critical for overall health and well-being. Getting adequate deep sleep is necessary for your brain and body to function and carry out the many processes required for maintaining health and functioning. 

Most people spend about one-third of their lifetimes sleeping, although over 33% of adults in the U.S. get less than the recommended seven hours of sleep per night. A lack of proper sleep puts you at greater risk of many health conditions, including neurological issues, cardiovascular disease, metabolic dysfunction, mood issues, and a weakening of the immune system. Not getting enough sleep can even increase oxidative stress and damage your DNA.

A functional medicine approach to restorative sleep uncovers and addresses underlying factors contributing to poor or inadequate sleep. This approach can help you address contributing and resulting health issues and instill healthy lifestyle habits of greater well-being.

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Understanding Sleep and Its Importance

Sleep is a state of unconsciousness during which your brain is less responsive to outside stimuli, and your body rests and repairs. But sleep is not just an inactive state; your brain and body have carefully orchestrated rhythms that ensure the process generally proceeds in an organized manner. This allows for restorative sleep, during which your body can detoxify, rebalance, and replenish hormones, repair damaged cells and tissues, process nutrients and emotions, and rest.

During this important time, you go through a cycle of physiological changes. The stages of restorative sleep are coordinated by the body’s internal clock, the circadian rhythm. This natural 24-hour cycle is influenced by the amount of light throughout the day and is usually aligned with nature’s cycles of darkness and daylight. One impact of your circadian rhythm is to send signals to your brain about when it is time to sleep and wake up with several hormones and neurotransmitters playing critical roles in the quality and duration of your sleep. 

These internal signals are influenced by environmental cues via the suprachiasmatic nucleus (SCN) in the hypothalamus, an area of the brain that controls many vital body functions. Darkness in your environment tells your brain to secrete the hormone melatonin that suppresses the excitatory neurotransmitter glutamate and stress hormone cortisol. These signals help prepare your body for slowing down and dropping into sleep. You need this circadian rhythm to remain synchronized and functioning correctly for your overall well-being, quality sleep, and neurological health.

The stages of sleep each have essential functions and are divided into two primary categories: non-rapid eye movement (NREM) and rapid eye movement (REM) rest, each of which has several stages. A typical sleep cycle moves through these stages in around 90-minute cycles throughout the night. As the night progresses, you generally experience longer and longer periods of REM sleep.

NREM sleep includes stages N1, N2, and N3. As you progress from awake to light stage 1 (N1) rest, the brain gradually becomes less responsive to sounds, smells, visual stimuli, and other environmental cues. As your sleep becomes more profound, you enter N2 as your brain waves become slower, and sleep spindles and K-complexes occur. In slow-wave sleep (N3), you reach the deepest and most restorative stage of sleep that you need for physical restoration, memory consolidation, and overall health. 

During REM sleep, you experience rapid eye movements, increased brain activity, and vivid dreaming while your body is prevented from other physical exercises. You need adequate REM sleep for proper cognitive function, learning, and emotional regulation. 

Common Sleep Disorders and Their Impact

Given how important it is to get adequate, high-quality sleep, it is not surprising that a lack of sleep can contribute to many health issues. Common sleep disorders such as insomnia, sleep apnea, and restless leg syndrome can have significant impacts on health and quality of life. 

Insomnia occurs when you have trouble falling or staying asleep and/or experience frequent waking during sleep. It is a common condition, impacting up to 59% of adults in the US. When insomnia becomes chronic, occurring at least three nights a week for a minimum of three months, it can increase your risk of many chronic diseases, including depression, hypertension, stroke, dementia, obesity, and diabetes. Insomnia also causes fatigue, excessive daytime sleepiness, irritability, and impaired functioning in many areas of life.

Sleep apnea is a potentially life-threatening sleep disorder that commonly goes undiagnosed. Up to 18 million people in the US have a diagnosis of sleep apnea, with at least another 4% suffering without a diagnosis. There are two main types of sleep apnea: obstructive sleep apnea, which impacts 10-30% of American adults, and central sleep apnea, which arises from the brain itself and affects less than 1% of adults in the US.

Another common sleep disorder that has significant health impacts is restless leg syndrome. This neurological condition impacts up to 10% of the population. It results in unpleasant urges to move the legs that disrupt restful sleep. It is thought that a combination of genetics and nutrient deficiencies like iron deficiency often contribute to this condition.

Given the significant health impacts of sleep disorders and the long-term lack of restorative sleep, it is essential to recognize and diagnose these disorders early so that they can be addressed appropriately. 

The Functional Medicine Perspective on Sleep

Functional medicine recognizes how critical restorative sleep is for health and well-being and approaches these sleep disorders with a personalized approach. This holistic approach to sleep issues seeks to integrate an understanding of the interconnectedness of many body systems to uncover underlying contributing factors and develop an individualized management plan. 

Many factors can contribute to sleep issues and disorders, including stress, lifestyle factors, and imbalances in the microbiome, micronutrients, and hormones. A functional medicine perspective on sleep considers these factors when developing a holistic approach to improving sleep. 

Physiologic and emotional stress can have a profound impact on your health, including your sleep. If you experience overwhelming acute and/or ongoing chronic stress, your sympathetic nervous system (fight or flight) can become overactivated, flooding your body with stress hormones like cortisol. When cortisol is too high or produced too often or at the wrong times, this can dysregulate melatonin production, contribute to systemic inflammation, and disrupt blood glucose levels, all of which create further stress and impair sleep. 

Stress also disrupts the average structural organization of rest and can impact the duration of each stage of sleep, resulting in disruptions during REM sleep and a decreased amount of time spent in deep sleep.

Lifestyle habits can contribute to stress and also prevent the natural syncing of sleep-wake cycles with light-dark cycles. Irregular sleep schedules, shift work, chronically staying up too late, not engaging in regular physical activity, and consuming substances, including alcohol, illegal drugs, and chronic caffeine, can all contribute to imbalances in sleep. In addition, a lack of exposure to natural light during the daytime combined with exposure to artificial light at night throws off circadian cycles and impairs sleep quality. Artificial light from electronic devices like computers, televisions, and smartphones emit blue light that sends signals of daylight to the brain. This prevents the natural nighttime rise in melatonin that helps you fall asleep.

Addressing Underlying Health Conditions

Many health conditions are impacted by and impact sleep. Common illnesses, including anxiety, depression, hormonal imbalances, and chronic pain, all affect the quality and quantity of sleep. For example, inadequate sleep is associated with significant increases in mental distress even after controlling for confounding variables, and mental stress and illness significantly impact sleep. Treating underlying causes of sleep issues can help bring greater balance to the body and improve overall health. 

The trillions of microorganisms living in your gut compose your gut microbiome. These microbes influence many aspects of your health, including impacting your circadian rhythm. When the balance of microbes in the gut gets disrupted (dysbiosis) this can affect circadian alignment and sleep. Gut microbes create signals that interact with genes regulating your circadian rhythms, impact the production of sleep-impacting hormones like cortisol, tryptophan, and melatonin, and influence sleep via the gut-brain axis.  

In addition, disrupted sleep, such as from shift work, creates stress and anxiety that can throw off the balance of microbes in the gut. This sets off a vicious cycle that disturbs sleep. Gut dysbiosis affects the function of the nervous and immune systems, contributes to inflammation, and creates further stress in the body. Combined, these impacts reduce your ability to cope with psychological and physical stress and have an additional impact on sleep and repair. 

Similar two-way interactions between the gut microbiome and sleep contribute to the ways in which depression can disrupt restorative sleep, and a lack of sleep can contribute to mood disorders. For this and other reasons, poor sleep is associated with a higher rate of depressive symptoms, and disturbances in sleep are common in mood disorders like major depression and anxiety.

Functional medicine for sleep-related health conditions recognizes these multidirectional relationships between sleep, mental health, and physical health. Taking this approach helps to target underlying health conditions and create a management approach that restores adequate rest and recovery time.

Assessing Sleep Health in Functional Medicine

Comprehensively assessing sleep health allows for the identification of individual factors that are contributing to imbalances and issues. A functional medicine assessment for sleep incorporates an evaluation of laboratory testing to look at biomarkers associated with sleep quality and duration, sleep diaries to assess factors impacting sleep, and questionnaires to determine underlying factors influencing sleep and related conditions. 

Fatigue is a common concern, with so many people living a non-stop lifestyle that doesn’t allow much time for quality rest. A clinical assessment can include exploring questions assessing how long someone is sleeping, how deep they are sleeping, how long it takes them to fall asleep, and how they feel when they first get up in the morning. Many formal questionnaires also exist to measure sleep quality, daytime sleepiness, and how a lack of sleep may be impacting daily activities. 

People can keep a simple sleep diary to give some insights into how much and how well they are actually sleeping, tracking when they fall asleep, how many times they wake and/or get up during the night, and when they get up and rise in the morning. They can also record when and why they are waking up in the middle of the night and how long these interludes last. 

Biometric data like heart rate, heart rate variability, respiratory rate, and oxygen saturation can be used to approximate sleep stages and evaluate sleep using algorithms that calculate information about your sleep. Such biometric data can be collected with wearable devices like a Fitbit or Oura ring. In-laboratory sleep studies have been the gold standard for assessing sleep disorders, but they bring the disruption of sleeping in a clinical setting. Emerging at-home sleep studies using wearable devices show good accuracy for diagnosing many conditions in a more familiar environment and may be used to diagnose some people with suspected sleep disorders like sleep apnea or restless leg syndrome. 

Functional medicine laboratory testing is also helpful for assessing underlying health issues that may be contributing to poor sleep. Hormone testing like the DUTCH Complete from Precision Analytical is also useful in looking into any hormonal issues that may be causing sleep disturbances. Having imbalanced patterns throughout the day and night can contribute to poor sleep by lowering melatonin, inducing hot flashes, and/or causing hypoglycemia. This test measures sex and adrenal hormones as well as provides a look at the daily free cortisol pattern, organic acids, and melatonin. 

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Nutritional Strategies for Improving Sleep

Many dietary factors can contribute to disruptions in sleep. Various nutrients impact hormones and neurotransmitters that influence sleep, certain foods can impact the quality of your sleep, and the timing of meals can have an impact on how well and deeply you sleep. There are specific dietary changes for sleep improvement that you can implement as part of a comprehensive approach to enhancing sleep quality. 

A sleep-supportive diet incorporates dietary support that provides nutrition for better sleep. For example, avoiding stimulants and other substances that can impact your brain’s function can help your circadian rhythm stabilize and your sleep becomes more regular. Avoid alcohol, especially within three hours of bedtime, as well as spicy foods and large meals close to bedtime. For optimal sleep and digestion, aim to finish eating any major meals three hours before going to sleep.

Similarly, it can help to avoid caffeine-containing foods and beverages later in the day, depending on your individual sensitivity level. This includes caffeinated sodas and teas, coffee, and chocolate. Some medications can also contain stimulants and/or caffeine, so discuss this with your physician or pharmacist. 

Imbalances in nutrients, hormones, and neurotransmitters can all contribute to sleep issues. For example, low iron, low magnesium, and low dopamine can contribute to restless leg syndrome. At the same time, vitamin B-12 is inversely correlated with sleep duration, a deficiency of 25(OH) vitamin D is associated with sleepiness and insomnia, and imbalances in folate are associated with sleep disturbances. Micronutrients like magnesium, vitamin D, and vitamin B6 are essential for the production and balance of many of the hormones and neurotransmitters that regulate sleep. 

Magnesium helps to increase GABA, a neurotransmitter that helps to slow down thinking and contributes to the onset of sleep. Foods rich in magnesium include leafy green vegetables, legumes, nuts, seeds, and whole grains.

‍Vitamin D has been shown to improve the time it takes to fall asleep and improve sleep quality and duration. ‍You can obtain vitamin D from sun exposure and by eating foods like oily fish (salmon, sardines, and tuna), cod liver oil, and mushrooms. 

Vitamin B6 is an essential nutrient for making serotonin and melatonin, hormones that are crucial for regulating your sleep cycles. Foods like chickpeas, beef liver, tuna, salmon, potatoes, poultry, and bananas can provide this vitamin in your diet.

The Micronutrient Test by SpectraCell Laboratories examines these and other essential vitamins, minerals, and nutrients to identify any deficiencies that may be contributing to sleep issues.

Herbal and Natural Remedies for Sleep

Herbal and natural remedies can be supportive of relaxation and sleep when needed. Some common herbal supplements for better sleep include magnesium, melatonin, valerian root, and lemon balm. It can also be helpful to consider any medications you are taking that may disrupt sleep and discuss your overall health plan with a healthcare professional. 

Magnesium is a crucial mineral involved in sleep and relaxation. Magnesium impacts levels of sleep-inducing neurotransmitters, with a deficiency of magnesium associated with poor sleep quality. Magnesium supplementation has been shown to increase melatonin, reduce cortisol, and improve subjective markers of insomnia, including sleep efficiency, sleep onset latency, and early morning awakenings. This mineral can be taken in supplemental form or absorbed topically with Epsom salt baths or magnesium oil spray. 

Your body naturally produces melatonin in response to darkness to help you fall and stay asleep. Exogenous melatonin supplementation has been shown to help synchronize circadian rhythms, improve the onset, duration, and quality of sleep, and act as an antioxidant. Melatonin may also help with jet lag and shift-work sleep issues, although studies have been small and sometimes inconclusive.

Amongst the commonly used natural remedies for sleep, valerian root is used to make it easier to fall asleep and improve sleep quality. It is generally safe for short-term use but should not be combined with alcohol or other sedatives. Lemon balm is another calming herb that is often combined with valerian root to help promote sleep and treat insomnia. This herbal combination helped 81% of people with minor sleep issues improve their sleep compared to a placebo in one study.

Medications can impact sleep in different ways. For example, certain antidepressants, beta-blockers, and nonsteroidal anti-inflammatory drugs (NSAIDs) can decrease melatonin, throwing off circadian rhythms and sleep. Other drugs impact nutrient levels that contribute to sleep-influencing hormones and neurotransmitters. Vitamin B6 levels are affected by some oral contraceptives, slowing the conversion of the neurotransmitter glutamate into gamma-aminobutyric acid (GABA) that helps to calm the brain and induce sleep. Certain diuretics can deplete magnesium, which is needed to calm the body and produce neurotransmitters involved in sleep.

Lifestyle Modifications for Enhanced Sleep

Sleep is a crucial part of your daily routine, and you can incorporate healthy sleep hygiene practices and lifestyle habits that will help you get more restorative rest. 

Establishing a regular sleep routine allows your body to more easily prepare for and settle into sleep. Aim to go to sleep and wake up at the same time each day as much as possible to help train your biological clock. For most people, it is helpful to get to bed before 11 pm and to sleep for between seven and nine hours, although each person’s sleep needs are unique. 

Avoid bright and blue light before bed and opt for activities like reading a book instead of using electronic devices like your phone or tablet. Raising your body temperature and relaxing your muscles and mind with a hot bath can help to induce sleep. Adding magnesium sulfate (Epsom salts) and lavender essential oil can also help to soothe the body and mind and lower cortisol levels. 

It is also helpful to create a sleep-conducive environment. Keep the bedroom dark with room-darkening shades and/or a comfortable sleep mask to block light. Decrease disruptive noises in your sleep space by closing windows, using ear plugs, and/or using a white noise generator or air filter. Aim to keep your bedroom at a comfortable temperature and sleep under bedding that can breathe and help you regulate your sleeping temperature. Also, be aware of avoiding sleeping near electromagnetic fields (EMFs) by placing the head of your bed at least eight feet away from EMFs from sources like outlets and appliances and keeping your phone outside of the bedroom when sleeping. 

Regular physical activity can help you manage chronic stress and get deeper sleep, but the timing can have an impact. Most people sleep better when they engage in aerobic exercise like cardio at least three hours before bedtime.

If you find yourself having trouble falling asleep or waking up during sleep, it can be helpful to avoid lying awake for more than 20-30 minutes trying to fall asleep and to instead leave your bedroom and go to a relaxing space to read or do a mind-body practice like meditation. If you wake up with lots of thoughts, try journaling and/or talking over them with a trusted friend or counselor. 

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Restorative Sleep: Final Thoughts

Sleep impacts so many aspects of health, and a lack of adequate restorative sleep can contribute to many chronic illnesses. Inadequate and poor quality sleep is a common occurrence with wide-reaching impacts. Therefore, optimizing sleep is crucial for maintaining long-term health and well-being.

A functional medicine approach recognizes and addresses the connections between sleep, health, and disease and the multi-directional communication between the nervous system, gastrointestinal tract, and immune system. hormones, nutrients, and neurotransmitters that facilitate these interactions. In this way, embracing functional medicine for sleep health provides a comprehensive, personalized approach to improving sleep, overall health, and well-being.