The foundational paradigm of yin-yang represents the fundamental forces of nature and life, manifesting as opposing yet complementary states which express unity in motion. Understanding insomnia from both TCM and modern biomedical perspectives requires recognizing these cyclical patterns inherent in our body, mind, and the natural world.
In the realm of traditional Chinese medicine (TCM), a profound perspective emerges on insomnia, sleep, and lifestyle, integrated within sophisticated schemas of disease causation and emotional interplay. This article explores the connection of ancient wisdom with modern scientific insights into sleep architecture, the glymphatic system, the hypothalamic-pituitary-adrenal (HPA) axis, circadian rhythms, and the microbiome. By delving into the TCM and biomedicine nexus, this article constitutes a detailed yet imaginative exploration for healthcare providers, with specific herbal formulas to treat patients experiencing insomnia.
Yin-Yang: A Foundation for Understanding Sleep
The natural circadian rhythm mirrors the cyclical movement of yin-yang. Yang energy rises with the sun, promoting activity, wakefulness, and productivity, paralleling the morning spike of cortisol. As daylight wanes, Yang recedes, and Yin ascends, encouraging rest, relaxation, and inward rejuvenation, coinciding with evening increases in melatonin. Harmonizing with this rhythm supports the entire hormonal system.
Balancing Yin, Yang, and the Free Flow of Qi and Blood
Healthy sleep in TCM requires:
- A harmonious balance of Yin (calming, restorative) and Yang (active, alert).
- Smooth, unobstructed flow of Qi and blood, essential for mental and physical tranquility.
- Clear and calm Shen (mind-spirit), rooted in ample Heart and Liver blood.
Disruptions in these areas, such as emotional stress (internal causes) or environmental factors (external causes like dampness or heat), can disturb sleep. Integrating this understanding helps target effective therapeutic strategies.
Harmonizing Internal Rhythms: Hormonal and Microbial Influences
Modern research highlights the critical roles hormones and microbiota play in maintaining sleep quality:
- Hormonal rhythms: The hypothalamic-pituitary-adrenal (HPA) axis orchestrates cortisol and melatonin production, closely aligned with circadian rhythms influenced by light exposure.
- Microbial rhythms: The gut microbiome exhibits its own circadian rhythm, affecting digestion, mood, immune health, and sleep.
Maintaining regular sleep schedules, managing evening light exposure, and consistent dietary habits synchronize these rhythms, mirroring TCM’s emphasis on lifestyle harmony.
Traditional Herbal Formulas and Western Integration
TCM herbal formulas effectively address imbalances underlying insomnia:
- Tian Wang Bu Xin Dan (Celestial Emperor’s Blend) nourishes Yin and calms the Shen, particularly beneficial for insomnia marked by difficulty staying asleep, anxiety, or restlessness.
- Xiao Yao San (Free and Easy Wanderer) harmonizes Liver Qi and blood, alleviating emotional stress and improving sleep disrupted by anxiety or mood fluctuations.
An integrative therapeutic pairing involves using Xiao Yao San during the daytime Yang phase (high cortisol) and Tian Wang Bu Xin Dan during evening Yin (high melatonin), effectively regulating circadian rhythms and supporting healthy sleep.
Additional formulas include:
- Bao He Wan (Digestive Harmony Formula) for insomnia from occasional food stagnation due to late or heavy meals.
- Suan Zao Ren Tang (Zizyphus Sleep Formula) for insomnia from overstimulation, emotional stress, or late-day caffeine intake.
Exercise and the Smooth Flow of Qi and Blood
Regular physical activity enhances the smooth circulation of Qi and blood, paralleling biomedical insights regarding exercise’s role in regulating cortisol levels, enhancing sleep quality, and supporting deep, restorative sleep. Exercise thus becomes integral to maintaining overall balance and harmony in body and mind.
The Role of Sleep Architecture
Sleep architecture in modern science refers to the structure of the various stages of sleep (REM and non-REM) that an individual cycles through during sleep. Disruptions in these cycles—whether from internal disharmonies or external disturbances—can lead directly to sleep disorders such as insomnia, while indirectly contributing to age-related cognitive decline, and psychoneuroimmunological dysfunction more broadly.
According to the canon of TCM, sleep is the time when the Shen and Hun can intermingle and restore balance to the mind and body. If either is disturbed, it may result in difficulties in falling asleep or staying asleep, which can be seen in TCM as issues of blood deficiency (difficulty in falling asleep) and yin deficiency (issues with staying asleep).
The Glymphatic System and TCM
Modern research into the glymphatic system shows it plays a crucial role in clearing metabolic waste from the brain during sleep. Pharmacological sleep-aids and excessive alcohol consumption disrupt the harmonious function of this delicate system, which can lead to chronic immune dysfunction at the level of the blood-brain barrier. This can impact memory, executive function, mood, and more.
Circadian Rhythm and Channel Theory Clock
The circadian rhythm is a fundamental aspect of human biology, orchestrating a wide array of physiological processes over approximately a 24-hour cycle. This internal clock helps regulate sleep-wake cycles, feeding patterns, hormone release, and many other bodily functions. Understanding the mechanisms and impacts of the circadian rhythm can provide critical insights into health and disease management.
The concept of circadian rhythm in biomedicine, which explains the body’s internal clock, parallels TCM’s channel theory clock, where Qi moves through different organ systems at specific times.
The Role of Light
Light is the most crucial external cue in regulating the circadian rhythm, a concept known as photoentrainment. Exposure to light in the morning advances the clock, making us wake up earlier, while light at night delays the clock, pushing our sleep time later. This influence of light explains why irregular light exposure, common in modern life due to artificial lighting and screen time, can lead to circadian rhythm disorders, such as delayed or advanced sleep phase disorder.
Light pollution disrupts circadian rhythms, significantly impacting sleep and overall health. According to a study published in the Proceedings of the National Academy of Sciences (PNAS), even minimal artificial light at night (LAN) suppresses melatonin, delaying sleep and elevating risks for chronic conditions such as diabetes and hypertension (Phillips, 2019). Further, a recent cohort study from China linked higher LAN exposure to a 17% increased risk of stroke, highlighting its detrimental cerebrovascular effects (Wu, 2024). Additional research in Frontiers of Neuroscience and Epidemiology connects long-term LAN exposure to heightened risks of Alzheimer's disease and cancer, compounding the public health crisis (Hurley, 2014; Voigt, 2024). Alarmingly, more than 80% of the global population—and over 99% in the US and Europe—now live under skies heavily polluted by artificial light, profoundly disrupting natural biological rhythms essential for health (Falchi, 2016).
Practical Implications
To maintain a healthy circadian rhythm, it is recommended to:
- Seek morning light exposure: This can help reset the circadian clock, particularly for those who have difficulty waking up in the morning.
- Maintain regular sleep schedules: Going to bed and waking up at the same time every day, even on weekends, helps reinforce the natural circadian cycle.
- Manage light exposure: Avoiding bright light, especially blue light from screens, before bedtime can help prevent delays in the sleep cycle.
Traditional Formulas for Harmonizing Circadian Rhythm and Nourishing Sleep
Kan Herb Company offers several excellent renditions of classic and time-tested Chinese medical formulas for addressing the complex realm of the night. Night is ruled by yin, and yin at its depth is expressed through the great deep waters of the Kidney system, and the fertile flexibility of the Liver system. Liver blood houses the ethereal soul (hún/魂), which wanders to and fro while we sleep, encountering ethereal qi and the qi of the environment, manifesting imagery, scenes, and sensations which we perceive as dreamscapes. Kidney jing and yin is the basis for the yin of the whole body, can be considered as the vast realm of the unconscious, and as the genetic information and patterns which have shaped the structure and function of the body-mind through the myriad fibers of time.
Tiang Wang Bu Xin Dan (Celestial Emperor’s Blend), adapted by imperial physician Xue Ji in the Ming dynasty from an original composition by Sun Simiao, is an elegant formula quintessential for yin conditions which involve the Kidney, Liver, and Heart, especially when the fire of the mingmen (Life Gate) is flaring due to excessive stress and aging resulting in a disconnect between Heart Fire and Kidney Water. Key symptoms to look for are warmth at night, restless sleep, trouble falling asleep, staying asleep, midnight awakening, and low-grade anxiety during the day. Just two or three of these symptoms is absolutely enough to consider recommending this formula.
Its original functions are described as follows:
Makes the heart tranquil, guards the spirit, augments the blood, secures the essence, fortifies one’s energy, strengthens the resolve, and causes people not to forget. It clears the three burners, transforms phlegm and saliva, dispels irritability, heat, eliminates fright palpitations, treats dry throat, and fosters and nourishes the Heart spirit.
Focusing on the functions of the Liver system, two formulas stand out as important agents for harmonizing the qi and blood. Whereas Celestial Emperor’s Blend focuses on connecting the Heart and Kidney (shaoyin) and descending the fire of the mingmen, generating fluids and stabilizing the mind, Xiao Yao San (Free and Easy Wanderer) centers around luxuriating the blood of the Liver and the qi of the Spleen. Modified with Mu Dan Pi and Zhi Mu, Xiao Yao San transforms to Jia Wei Xiao Yao San (Relaxed Wanderer), resolving Heat, and supplementing the qi dynamic of the Liver system to improve the capacity for a sense of ease and clarity of mind.
Now, why should these formulas be considered within the context of sleep, yin, and insomnia?
When the Liver blood is full and nourished, the aspects of mind which involve strategizing, planning, envisioning, and judging are balanced and clear. The emotional realms of frustration, anger, and envy are moderated, and the benevolent qualities of generosity, forgiveness, and empathy are accessible and effortlessly expressed. Aches and pains are smoothed over by the nourishing flow of Liver qi and blood, tendons and ligaments are supple, and the ethereal soul is at home within the vastness of jueyin—the absolute yin.
Zhang Jingyue: 'When the [heat] qi fights against the liver, then the liver qi turns into disorder. Hence [the patient] talks crazily and is frightened. .. Extreme heat generates wind. Wind excess moves into the four limbs. Hence hands and feet are restless. When wood evil invades the soil, it will proceed to the stomach. When the stomach loses its harmony, one’s sleep is not peaceful.'
Aligning Relaxed Wander in the day, as cortisol is at its zenith, and Celestial Emperor’s Blend in the evening, when melatonin is increasing, is a potent and practical approach for regulating the circadian rhythm. This formula pairing can be considered for anyone who is on a tight schedule, experiences chronic stress, is showing signs of dysregulated sleep, and importantly, presents with idiopathic dysfunction such as high cholesterol, insulin resistance, depression, IBS, or anxiety. Circadian rhythms are easily disrupted by light at night and can have wide ranging effect upon our health.
The Neijing and Seasonal Influences on Sleep
No overview is complete without waxing canonical...
The Neijing (Inner Classic) stipulates that human activities, including sleep, should align with the seasonal variations in environmental Qi. The text emphasizes waking and sleeping with the natural light patterns to preserve health.
The three months of spring,
they denote effusion and spreading.
Heaven and earth together generate life;
the myriad beings flourish.
Go to rest late at night and rise early.
Move through the courtyard with long strides.
Dishevel the hair and relax the physical appearance,
thereby cause the mind [to orient itself on] life.
Give life and do not kill.
Give and do not take.
Reward and do not punish.
This is correspondence with the qi of spring and
it is the Way to nourish life.
Depression, Emotion, and Insomnia
Seasonal changes can influence mood and sleep, potentially leading to depression and insomnia. The influential Ming dynasty physician Zhang Jingyue (c. 1563-1640) identified emotional stagnation as a critical factor, where unexpressed emotions lead to yu (stagnation), exacerbating sleep disturbances.
The Role of Exercise in Promoting Healthy Sleep
Exercise plays a vital role in enhancing sleep quality, a notion that aligns well with both modern biomedical insights and traditional perspectives. Engaging in physical activity is beneficial for sleep for several reasons, which can be examined through both physiological and traditional Chinese medicine (TCM) lenses.
Physiological Benefits of Exercise for Sleep
From a biomedical viewpoint, regular physical activity helps regulate the secretion of stress hormones like cortisol, produced by the HPA axis. By moderating stress hormone levels, exercise can promote a more relaxed state conducive to falling asleep and maintaining deep sleep cycles. Exercise also increases the time spent in deep sleep, the most physically restorative phase of sleep, which helps in muscle repair, boosting immune function, and reducing stress and anxiety.
Traditional Chinese Medicine’s holistic view of insomnia provides a rich framework for understanding sleep disorders through both traditional and modern lenses. By integrating these insights, healthcare practitioners can approach insomnia not just as a symptom but as a complex interplay of body, mind, and environmental factors, paving the way for more personalized and effective treatment strategies.