How do you effectively diagnose sleep issues?
Most “sleep studies” conducted in a lab struggle to diagnose sleep problems beyond apnea. Here’s how to better measure sleep issues, and how to address them.
The science is clear that we need adequate quantity and quality of sleep to support optimal metabolic health and overall health. However, how to achieve good quality and quantity of sleep isn’t always as clear, at least beyond the basics of setting up a sleep routine, getting your room as dark as possible, and eliminating distractions.
When people experience sleep issues, a physician may refer them for a sleep study, or polysomnogram (PSG). A PSG involves an overnight stay in a lab, where medical professionals glean data from your sleep physiology using various sensors. It is also valuable for diagnosing certain sleep disorders, such as sleep apnea. However, given the artificial environment and the single night of data collection, sleep studies have limitations and are just one part of a comprehensive sleep evaluation.
That’s because sleep is complicated and affected by many factors, from chronic health conditions and their medications or treatments to behavioral and lifestyle factors. Here’s a deeper look at sleep quality and its potential disruptors.
What constitutes sleep quality?
The Centers for Disease Control and Prevention (CDC) recommends that adults sleep seven to nine hours each night. But duration doesn’t address quality. What defines good sleep? It comes down to uninterrupted sleep and healthy cycling of sleep stages, or “sleep architecture.”
We go through several sleep cycles per night, each ranging from 90 to 120 minutes. Adults need three to five relatively uninterrupted sleep cycles. Each cycle also involves four sleep stages: three of non-rapid eye movement (NREM) sleep (the third accounting for our deepest level) and one of rapid eye movement (REM) sleep before we either start the next cycle or wake up.
However, our sleep architecture can become unstable if we have interruptions either caused by or leading to autonomic nervous system dysfunction. The autonomic nervous system has two main branches: sympathetic and parasympathetic. Our sympathetic nervous system is our “fight or flight” system. Its activation increases heart rate, breath rate, blood pressure, body temperature, and more. In short, it helps us react quickly to real-life situations, but it can also be a source of stress, insomnia, and poor sleep. Our parasympathetic system is our “rest and digest” system. Its activation lowers heart rate, blood pressure, and many biological functions that counteract the sympathetic nervous system.
Sleep disorders are associated with heightened activation of the sympathetic nervous system, which can have many different root causes, from mental or physical conditions to environmental and behavioral factors.
What conditions or other issues can interfere with sleep?
Many factors can affect sleep, including underlying mental or physical health conditions, neuro-developmental and degenerative issues, environmental influences, behavioral factors, and sleep disorders.
Mental health factors
If someone has anxiety or post-traumatic stress disorder (PTSD), they may experience hypervigilance, a state of heightened arousal where the brain is constantly assessing or preparing for a threat even when no danger is present. Hypervigilance means the sympathetic nervous system tends to be more easily activated than the parasympathetic nervous system, and the imbalance can impact sleep. However, when people treat the underlying causes of PTSD or anxiety, sleep usually improves. Major depression is also linked to sleep issues like insomnia, and likewise, trouble sleeping can worsen depression. Depression and anxiety often lead to an imbalance in autonomic function consistent with sympathetic overactivity that impairs sleep.
Neurodevelopmental and Neurodegenerative Disorders
Neurodevelopmental disorders such as autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorders (ADHD) may impact sleep, as well as be associated with certain sleep disorders. Over-activation of the sympathetic nervous system and a decrease in parasympathetic activation are noted in ASD, as well as problems with sleep timing mechanisms, including melatonin hormonal dysregulation. The links between poor sleep and ADHD may be attributed to multiple factors, including the use of stimulant medications, iron deficiency, and maladaptive behaviors and thoughts, which lead to dysregulation of the autonomic nervous system. In addition, many children and adults with ADHD have underlying sleep disorders such as sleep apnea and restless legs syndrome, which can worsen and even cause ADHD symptoms.
Neurodegenerative conditions, such as Parkinson’s disease, multiple sclerosis, Alzheimer’s disease, and other dementias, have bidirectional relationships with poor sleep quality and sleep disorders that impact both the neurodegenerative condition and the adequacy of sleep and recovery.
Additional health factors
Any pain condition—whether migraine, endometriosis, fibromyalgia, arthritis, neuropathy, and more—can also hinder sleep quality and quantity. Conversely, sleep inadequacy can worsen pain by lowering pain thresholds and perceptions of pain. Although multiple mechanisms may be involved in the associations between chronic pain and poor sleep, some theories and findings point to the relationship between autonomic nervous system dysregulation and altered sensitivity to pain.
Environmental factors
Light pollution, excessive noise, indoor and outdoor air quality, high room temperature, and multiple environmental elements can cause or exacerbate sleep issues. Artificial light exposure at night can suppress the release of melatonin, which helps prepare us for sleep, and activate brain centers associated with waking. Noise can cause sympathetic nervous system arousal, leading to fragmented sleep. Pollution causes systemic and respiratory inflammation that can trigger the sympathetic nervous system. With indoor air, higher CO2 levels and higher levels of volatile organic compounds (VOCs) are implicated in poor sleep, though more research is needed on the mechanisms involved. Higher room temperatures increase wakefulness, reduce REM and deep non-REM sleep, and interrupt sleep cycles in REM and non-REM sleep through alterations in the body’s natural cooling systems.
Behavioral factors
Sleep is ultimately a biological behavior impacted by our activities and habits. For example, inconsistent sleep-wake times (due to shift work, staying up later or sleeping in on weekends, etc.), late-night exposure to artificial blue light from devices, and a sedentary lifestyle all contribute to less sleep or lower quality sleep. Inconsistent sleep times disrupt the body’s circadian rhythms, our internal 24-hour clock. Exposure to artificial light before bed may inhibit melatonin production needed for sleep initiation and maintenance and cause wake-promoting systems in the brain to remain active. A sedentary lifestyle appears to negatively alter sleep architecture by decreasing NREM sleep and increasing REM sleep, which could adversely affect well-being and our perception of feeling rested.
Sleep disorders
Ultimately, many medical and psychological conditions are associated with sleep disorders. In fact, a well-known bidirectional relationship exists between inadequate sleep caused by an untreated sleep disorder and maladaptive lifestyle choices or environmental factors, and other medical or mental health issues. Here’s a breakdown of some of the primary sleep disorders:
- Insomnia. Insomnia can mean difficulty falling asleep, staying asleep, achieving uninterrupted sleep, or waking up too early before getting enough sleep. It is the most common sleep disorder. In addition, other sleep issues/disorders, medical conditions, and even treatments can cause the symptoms of insomnia. It can also be caused by inadequate sleep hygiene or increased cognitive arousal when going to sleep, referred to as psychophysiological insomnia. Genetics certainly play a role in some cases since we know that familial anxiety, depression, and your stress response may impact your risk of insomnia.
- Sleep apnea. Sleep apnea is another common sleep disorder where breathing temporarily and repeatedly stops or is reduced during sleep. Since all humans experience relaxation in the upper airway during sleep, which commonly leads to snoring and some sleep apnea, the diagnosis of sleep apnea depends upon how frequently it occurs and the impact on your physiology. Medically, the condition is categorized as obstructive sleep apnea (OSA), central sleep apnea (CSA), and complex sleep apnea syndrome (CXA). In OSA, the airway collapses or partially collapses throughout sleep cycles, often worsening during REM sleep and while lying supine. Several factors increase the risk of OSA, including airway anatomy and physiology, lifestyle factors, other medical conditions, and genetics. CSA is much less common than OSA and occurs when there is a miscommunication between the brain and muscles involved in breathing. This can be a result of heart failure, stroke, altitude, or even some medications. In CXA, both OSA and CSA are present. Often, CXA presents when someone with OSA initially begins treatment with positive airway pressure (PAP) such as continuous PAP (CPAP) that physiologically recalibrates respiratory signals. In general, sleep apnea is not a condition to leave untreated since studies show it can lead to significant cardiovascular, cardiometabolic, mental health, and safety issues.
- Narcolepsy. Narcolepsy is a rare neurological disorder that has a genetic predisposition and is believed to be caused by an autoimmune response that destroys wake-promoting neurons in the brain, specifically orexin/hypocretin cells. People with narcolepsy may fall asleep unexpectedly during the day, have sudden muscular failure with emotions, called cataplexy, and experience fragmented sleep.
- Restless Legs Syndrome (RLS). Restless legs syndrome is a sensorimotor disorder that results in uncomfortable sensations or urges to move the legs or other parts of the body while awake and at rest. It tends to occur more often in the evening and at night can lead to insomnia due to RLS symptoms or recurring periodic limb movements during sleep (PLMS). PLMS may also happen in other conditions such as Parkinson’s disease, multiple sclerosis, and narcolepsy, as well as with advancing age and in association with certain medications. Also, Periodic Limb Movement Disorder involves PLMS and daytime dysfunction not caused by another medical or sleep condition.
- Parasomnias. Parasomnias are a category of sleep disorders that involve unusual behaviors during or in transition to/from sleep. They are further divided into two groups of disorders, one happening during non-REM and the other occurring in REM sleep. Common non-REM parasomnias include sleepwalking and night terrors, while REM parasomnias can be common, as noted with nightmare disorder and sleep paralysis, or more rare, such as in REM sleep behavior disorder.
Sleepwalking, also called somnambulism, involves getting up, moving around, and sometimes engaging in wake behaviors such as eating or driving during NREM sleep. Night, or sleep, terrors are episodes involving screaming, running, or what would appear to an observer as someone trying to escape something terrifying. In reality, it’s an NREM parasomnia that usually resolves spontaneously and with no memory of the event. In contrast, nightmare disorder is a pattern of intense nightmares that occur during REM sleep, and which are clearly memorable for people. Sleep paralysis involves the inability to move when falling asleep or waking up and is sometimes associated with hallucinatory experiences. Finally, REM sleep behavior disorder (RBD) is characterized by acting out dreams during REM sleep, which can result in injuries and dangerous behaviors while asleep.
How can you measure and improve sleep quality?
We can measure sleep quality in multiple ways, from at-home wearables to FDA-cleared home-based sleep testing devices and polysomnography. Improving sleep quality requires a multidisciplinary approach that considers the person’s psychological makeup, behaviors and habits, sleep environment, sleep routines, schedules, lifestyle factors, and individual sleep physiology. To uncover the root causes of sleep problems and symptoms, it takes more than sleep testing or medical visits to personalize a program.
Wearables and Nearables
Wearables are consumer devices like smartwatches, wristbands, rings, and chest bands that contact the body to measure one or more physiological variables during sleep. Depending on the device, consumer wearables often measure movement, heart rate, blood flow, blood oxygen level, or temperature to estimate sleep architecture and patterns over time. Like wearables, nearables are also consumer devices; however, they don’t directly contact the body. Instead, they use radio waves and other non-contact technologies to discern sleep physiology. Both wearables and nearables can estimate your sleep duration and timing but are less helpful in determining sleep architecture or quality. In addition, consumer devices can’t diagnose sleep disorders and can lead to erroneous information or, worse, a missed diagnosis.
One measure that helps determine sleep quality is heart rate variability (HRV), which is the variation in time between heartbeats. During sleep, your HRV changes according to the activity of your autonomic nervous system, which can reflect changes in sleep stages. When consumer devices implement HRV they often use it as an additional metric for determining the presence of NREM and REM sleep.
While HRV is often used with other metrics to determine sleep architecture, it is not the same as PSG detection of sleep stages. For reference, a rough breakdown of healthy sleep architecture by sleep stage looks something like this:
- NREM 1 = less than 5% of sleep
- NREM 2 = about 50% of sleep
- NREM 3 = 20-25% of sleep
- REM = 20-25% of sleep
Often wearables lump NREM1 and NREM2 together. For example, Apple Watch uses “core” sleep, while Oura and Whoop call the combination “light” sleep. These wearables also refer to NREM3 as “deep” sleep.
Several wearables use HRV as a singular metric. In those cases, it may be a proxy for how well your autonomic nervous system operates. If HRV is low, it could mean that you have over-activation of the sympathetic nervous system. Some research suggests that healthy adults have an average HRV of 42 milliseconds, within a range of 19-75 milliseconds. However, the absolute value of a single HRV measure is influenced by many factors, from the specific variables and HRV calculations used to factors like age, sex, and the presence of certain diseases. Typically, a lower HRV indicates higher stress levels, reduced sleep-related recovery, and is associated with some chronic diseases.
Polysomnography
Laboratory sleep testing is referred to as polysomnography (PSG). This clinical test evaluates multiple simultaneous channels of data, including EEG, EOG, ECG, EMG, pulse oximetry, accelerometry, respiratory effort, snoring, and video, to analyze sleep stages and sleep architecture and detect sleep disorders utilizing rules and standards established by the American Academy of Sleep Medicine.
PSG is considered the gold standard for diagnosing many sleep disorders, but some limitations exist. Since it is a single-night test performed in a laboratory setting, it doesn’t reflect a usual night of sleep at home. A disruption from your evening routine, differences from your home sleep environment, and the addition of testing equipment often alter results, which may cause changes in sleep physiology referred to as the “first night effect.” In addition, behavioral, psychological, and environmental factors that impact sleep quality are not measured by PSG testing. While laboratory sleep studies are a mainstay in diagnosing sleep apnea and other sleep disorders, they don’t consider the night-to-night variability of many symptoms and sleep disorders.
Home sleep apnea testing
Your doctor may also prescribe an at-home sleep test, typically utilizing fewer sensors than PSG to uncover possible sleep apnea. While home sleep apnea tests are less sensitive than PSG, they can be performed over multiple days, which improves their diagnostic accuracy. While home sleep apnea tests can diagnose sleep apnea, they can’t diagnose other sleep disorders or track routine sleep physiology.
Personalized sleep performance programs
Some biotech companies, such as Absolute Rest, offer direct-to-consumer programs that scientifically evaluate your sleep physiology and associated behavioral, environmental, and psychological biomarkers to create personalized programs for sleep improvement. Programs may include home-based environmental testing, PSG, FDA-cleared wearable sleep devices, detailed sleep health, and medical, behavioral, and psychological evaluations. [More on this below.]
How can you improve sleep?
Treatment for sleep issues and disorders varies from person to person and condition to condition. For example, to treat obstructive sleep apnea, people are often prescribed a CPAP machine to keep the airway open while sleeping. Similarly, other types of positive airway pressure delivery, such as bilevel positive airway pressure, can be used to treat apnea and other sleep-related breathing issues. Restless legs syndrome is sometimes treated with prescription medications, iron supplementation, electronic devices, or lifestyle changes. In addition to specific therapies, people may need to address environmental, behavioral, and psychological factors that disrupt sleep.
Cognitive behavioral therapy (CBT) is one method for addressing sleep-related thoughts and behaviors associated with insomnia. CBT for insomnia (CBT-i) is the most effective and long-lasting treatment for psychophysiological insomnia. CBT-i employs various techniques for relaxation, improving sleep-promoting environments and behaviors referred to as “sleep hygiene,” reframing maladaptive thoughts, and more. If someone has a history of trauma that’s causing an imbalance between the sympathetic and parasympathetic systems, a psychologist may be able to teach them techniques for activating the parasympathetic nervous system, as well as implement other CBT and psychological approaches to reduce the impact of trauma on sleep, and vice versa.
Understanding the context surrounding parasomnias is essential to determining the best course of treatment. Some parasomnias may be related to medication effects, like selective serotonin reuptake inhibitors (SSRIs), statins, beta-blockers, and some smoking cessation products. In other cases, such as with RBD, parasomnias may be caused by other sleep disorders such as sleep-disordered breathing or be the harbinger of a neurodegenerative disorder like Parkinson’s or Lewy body dementia.
Understanding the impact of sleep timing
We all have an internal clock that orchestrates the myriad of rhythms from our environment, many biological systems, and behaviors. Your circadian rhythm system determines when you sleep, eat, and perform at your best and worst. Each of us has a different master clock that creates our “chronotype,” meaning whether we are an early bird, night owl, or somewhere in between. To determine your chronotype, you can take the Morningness-Eveningness Questionnaire (MEQ), a method that’s been around since the late 1970s and is still used today. Biological measures of chronotype involve well-controlled laboratory measurements of core temperature, dim light melatonin secretion, and other hormones associated with sleep and wake. Some who experience a misalignment between their chronotype and activity schedule (i.e., work, school, family obligations) may have insomnia, daytime sleepiness, or a combination of the two. An example of a common sleep-wake misalignment is “social jetlag,” where sleep timing differs markedly from weekday to weekend, causing significant performance problems due to inadequate sleep. Our chronotype is genetic, and we can’t always entirely change our schedules to match our chronotypes, but minor adjustments and specific behavioral, medical, and light therapy approaches may help. One recently published intervention for youths at risk of circadian rhythm dysregulation, called Transdiagnostic Intervention for Sleep and Circadian Dysfunction (TranS-C), helps build behaviors that, in some ways, contribute to better sleep compared to receiving psychoeducation about sleep.
Absolute Rest’s approach to diagnosing and treating sleep disorders
The team at Absolute Rest has set out to bring medical and scientific evaluations of sleep together with psychological, behavioral, and environmental metrics to quantify a multitude of external and internal influences that impact sleep. “Bringing together the science, medicine, psychology, behavioral, and environmental components of sleep allows us to determine the relative impact of many distinct contributors to sleep quality and adequacy,” says Jeffrey Durmer, MD, PhD, Chief Medical Officer. “Typically, physicians provide a targeted and often one-dimensional approach to improving sleep; however, sleep problems are by nature multidimensional. Sleep exists at the confluence of your mind, physiology, habits, and environment. Sleep-based root cause analysis means approaching from all angles and implementing interventions with precision and purpose.”
In terms of testing, Absolute Rest clients receive in-home PSG testing over two nights and an FDA-cleared sleep testing device that measures autonomic nervous system balance, among many other measures. “Because our autonomic nervous system (ANS) is highly sensitive to disturbances that can arise from many sources during sleep, we use an ANS sleep diagnostic and management device as an objective physiological monitoring tool. By continuously measuring the ANS, we can quantitatively demonstrate the impact of the environmental, physiological, behavioral, and psychological interventions designed for a specific individual,” says Durmer.
In addition to traditional polysomnographic measures of sleep, the ANS sleep testing (AST) device employs a well-validated algorithm to evaluate sleep quality called cardiopulmonary coupling (CPC). CPC uses spectral power analysis and coherence coupling of HRV and respiratory rate variability to determine sleep stability, moment-to-moment parasympathetic and sympathetic tone, and specific sleep metrics associated with different sleep pathologies.
At Absolute Rest, testing is just the beginning of the program. “For 90 days, we implement interventions,” Durmer explains. “We monitor objective outcomes from daily AST results in conjunction with clinically validated subjective surveys, clinical feedback from our psychological and medical sleep intervention teams, and outcomes reported by our Clinical Sleep Specialist team, who continuously interact with participants throughout their program.”
Absolute Rest pairs clients with master’s level Clinical Sleep Specialists who navigate and coordinate the various evaluations and interventions offered by the program. Based on metrics from PSG, AST, intake interviews, validated psychological, behavioral, and sleep questionnaires, blood tests, medical and psychological consultations, and many other measures, a specific treatment plan is created for each client. Programs may include medical, dental, and psychological therapies, as well as changes to environments, behaviors, mindfulness, and many other scientifically proven approaches to improve sleep quality and daytime performance.
A typical example of how Absolute Rest operates holistically can be seen in how it handles sleep apnea. Durmer stated that “diagnosing sleep apnea is not difficult, especially when diagnosing people at home. Combining a high fidelity home PSG for two nights with ongoing AST allows us to clearly identify the type (or phenotype) of sleep apnea, the night-to-night variability of sleep apnea expression, and causes of apnea exacerbation.” When implementing a treatment to control sleep apnea, Absolute Rest begins with a low-impact approach designed to improve laminar nasal airflow, reduce airway inflammation, restrict supine sleep and mouth breathing, and optimize the natural state of breathing during sleep using myofunctional exercises. “In some cases, we refer clients to ENT physicians for anatomic evaluations or treatments focused on airway obstructions. In other cases, our low-impact approaches successfully treat sleep apnea alone. Still, even clients who require additional apnea treatments such as oral appliance therapy (OAT), a CPAP device, or combination therapy benefit from starting with a low-impact approach,” says Durmer. The fact is that 50% of people prescribed a CPAP machine don’t use it. By first improving a client’s natural sleep-related breathing abilities, Absolute Rest markedly improves the success of medical treatments for sleep apnea like OAT and CPAP.
Takeaway
Ultimately, sleep improvement is not one-size-fits-all. Sleep is dependent on many unique physiological, psychological, behavioral, and environmental factors that collectively determine its quality. Finding a solution for what disrupts your sleep involves making accurate, longitudinal measurements, applying scientifically valid interventions, and, when appropriate, implementing medical and psychological therapeutics in a personalized approach with professional, caring support.
Note: This article was completed in collaboration with Absolute Rest, but Levels receives no compensation from and has no formal relationship with the company.
**
**See how sleep impacts your health
Levels offers fast, simple food logging to help you see how food and lifestyle affect your health through macro tracking, habit building, and customized insights and advice. Levels members can also incorporate biomarker data like real-time glucose and metabolic blood testing for an even more personalized experience. Click here to get started with Levels.
