The Suwen Seasonal Prescriptions: What the Yellow Emperor Actually Said
The most important passage in all of Chinese sleep medicine is found in Chapter 2 of the Suwen (Simple Questions), the foundational text of the Yellow Emperor's Inner Canon, written approximately 2,200 years ago. Titled 'Si Qi Tiao Shen Da Lun' (On Regulating the Spirit According to the Four Seasons), this chapter contains an explicit sleep prescription for each season. Spring: 'Go to rest late in the night, rise early, and stroll in the courtyard with hair unbound, body relaxed.' Summer: 'Go to rest late in the night, rise early, do not tire of the sun. Keep the spirit free from anger, and let the energy blossom outward like flowers in bloom.' Autumn: 'Go to rest early in the night, rise early, rising with the rooster.' Winter: 'Go to rest early in the night, rise late, rising with the sun, in the manner of the dormant will.' Notice the pattern — the prescriptions form a perfect bell curve of sleep duration. In summer, when days are longest, sleep is shortest and the emphasis is on energetic living. In winter, when days are shortest, sleep is longest and the emphasis is on conservation and dormancy. Spring and autumn occupy the middle positions, with autumn leaning toward earlier rest (the days are shrinking) and spring leaning toward later rest (the days are lengthening). This is not mystical instruction — it is a precise biological program that mirrors the photoperiod, encoded in the founding text of Chinese medicine.
- The Suwen prescriptions are not about exact clock times — they are about relative timing to the sun. Translate them to your latitude.
- Print the four prescriptions and review them at each solstice and equinox — this is the classic TCM practice of seasonal self-assessment.
- The phrase 'with hair unbound' in spring is not poetry — it's a prescription for loose, unrestricted movement that lets Yang Qi emerge freely.
"The three months of spring are called the time of emerging and unfolding. Heaven and earth both give birth, and the myriad things flourish. Go to rest late in the night, rise early, and stroll in the courtyard with hair unbound, body relaxed — this is the way to harmonize with the Qi of spring."
Why Seasonal Sleep Makes Biological Sense: Photoperiod, Melatonin, and SAD
Modern sleep science has spent the last three decades confirming what the Suwen asserted two millennia ago: human sleep is seasonally modulated. The primary driver is photoperiod — the length of daylight between sunrise and sunset — which varies by as much as 6 hours across the year at mid-latitudes. When daylight hours shrink, the timing of melatonin secretion shifts. Melatonin is the darkness hormone: the pineal gland begins secreting it approximately 2 hours before your biological bedtime, and the duration of melatonin secretion is directly proportional to the length of the dark period. In winter, that dark period is long — so melatonin secretion extends, and the natural sleep window lengthens. In summer, the dark period is short — melatonin secretion is compressed, and the natural sleep window shortens. A 2019 systematic review in Sleep Medicine Reviews examined 26 studies on seasonal sleep variation and found consistent evidence that total sleep time increases in winter (by roughly 20-40 minutes on average) and decreases in summer, with the winter pattern associated with earlier bedtimes and later wake times. A 2018 population study of nearly 3,000 participants published in the Journal of Sleep Research found that participants slept significantly longer and woke later in winter, even when accounting for work schedules and artificial lighting. Seasonal affective disorder (SAD) is the pathological extreme of this gradient: in vulnerable individuals, the winter photoperiod fails to phase-shift adequately, and the resulting circadian misalignment produces depression, hypersomnia, and carbohydrate cravings. The Western clinical response — bright light therapy in the morning — is a technological translation of the TCM prescription to 'wake with the sun' in winter. The ancient advice and the modern device are aimed at the same biological target.
- Your melatonin curve is your sleep script. Track your sleep for a week at each solstice and compare — you will see the seasonal shift in your own data.
- Artificial light in the evening (particularly blue light from screens) flattens the seasonal difference, confusing your photoperiod detection.
- If you live at a latitude where the seasonal daylight swing exceeds 4 hours, seasonal sleep adjustment matters more for you than for someone near the equator.
"The Qi of heaven and earth circulates in cycles of growth and harvest, fullness and emptiness. To sleep in harmony with these cycles is to preserve the Jing and live long."
Spring (Liver Time): Sleep a Bit Later, Wake Early, Move Gently
Spring is the season of wood and the Liver — of emergence, growth, and outward movement. The Suwen prescription is to 'rest late, rise early,' which translates to a bedtime approximately 30-60 minutes later than winter and a wake time at or just before sunrise. The Liver governs the smooth flow of Qi, and in spring that flow should be encouraged outward: this is the season for gentle movement (tai chi, walking, qigong) and for releasing the stagnation accumulated during winter's dormancy. For sleep, the spring pattern has a signature problem: Liver Qi stagnation. When the Liver's rising energy encounters a blocked or stiff body — too much sitting, too much screen time, too little movement — the Qi becomes stuck and transforms into heat. That heat rises at night to disturb the Shen. Spring sleepers often report waking between 1-3 AM (the Liver hour) or feeling physically restless at bedtime. The spring prescription: wake with the sun (earlier than winter), move the body in the morning (before 10 AM, to disperse Liver Qi outward), and keep the bedroom temperature slightly cool to balance the rising warmth of the season. Spring is also the season to clear Liver Fire through diet — reduce fried foods, alcohol, and late-night eating, and increase leafy greens and citrus. Your spring bedtime should land 30-60 minutes earlier than your summer bedtime, roughly mirroring the sunset curve.
- Morning movement is non-negotiable in spring: 15 minutes of walking or tai chi before 10 AM disperses Liver Qi and dramatically reduces 1-3 AM waking.
- If you wake at 1-3 AM in spring, treat it as a Liver Qi signal: add Liver-soothing herbs (chrysanthemum, goji berry tea) and reduce alcohol.
- Spring is the season to try a slightly earlier wake time than your winter schedule — even 15 minutes of morning light exposure resets your Liver-pattern circadian phase.
"The Liver corresponds to spring. It is the general of the army, and its Qi is like the sprouting wood — it must emerge and extend freely, or it becomes constrained and generates heat."
Summer (Heart Time): Shorter Sleep, Midday Rest, Guard Against Heat
Summer is the season of fire and the Heart — of maximum Yang, maximum daylight, and maximum outward expression. The Suwen prescribes the shortest sleep of the year: 'rest late, rise early, do not tire of the sun.' The summer sleeper needs roughly 30-60 minutes less nocturnal sleep than in winter, and the ancient prescription compensates for that with a midday rest — the siesta that remains a cultural institution across the Mediterranean and much of Asia. Modern chronobiology supports the siesta: the human body has a natural biphasic rhythm, with a secondary sleep propensity window in the early afternoon (roughly 1-3 PM) driven by the circadian system's 'afternoon dip.' In summer, when nocturnal sleep is compressed, this afternoon window becomes more biologically important. The summer sleep signature problem is Heat disturbing the Shen: the Heart governs the Shen, and when summer heat accumulates in the body — from hot days, spicy food, or overexertion in the sun — the Shen becomes agitated at night. Summer sleepers experience vivid dreams, night sweats, palpitations, and a feeling of heat at night. The prescription: sleep with the windows open if safe (or use a fan), keep the bedroom at 18-21°C, choose light cotton bedding, avoid heavy evening meals, and protect against excessive heat with cooling foods (watermelon, mung bean soup, cucumber). The siesta should be 15-30 minutes, timed between 1-3 PM, and never longer than 45 minutes (longer naps produce sleep inertia and can interfere with nocturnal sleep).
- A 20-minute afternoon rest between 1-3 PM is not laziness — it is the seasonal prescription and your biology's second sleep window.
- Summer insomnia often results from trying to maintain winter sleep duration in summer. Shortening your nocturnal sleep by 30 minutes may paradoxically improve its quality.
- Mung bean soup (Lü Dou Tang) is the classic summer sleep aid in Chinese food therapy — it clears Heart Fire and reduces night agitation.
"The three months of summer are called the time of flourishing and fullness. Heaven and earth interact, and the myriad things flower and bear fruit. Go to rest late, rise early, and do not tire of the sun — let the spirit bloom outward like the flowers."
Autumn (Lung Time): Early to Bed, Early to Rise, Like the Chickens
Autumn is the season of metal and the Lungs — of harvesting, consolidation, and letting go. The Suwen prescription is unambiguous and memorable: 'rest early, rise early, rising with the rooster.' The rooster crows at first light, which in autumn means a wake time at sunrise — earlier than summer, and a bedtime earlier than summer by roughly 30-60 minutes. The autumn sleep pattern is the mirror image of spring: where spring's problem is Liver Qi rising and getting stuck, autumn's problem is Lung Qi deficiency and grief. The Lungs govern grief in TCM, and the shortening days of autumn are classically associated with melancholy — the same seasonal mood shift that Western medicine tracks as the autumn onset of seasonal affective disorder. Autumn sleepers often wake early (3-5 AM, the Lung hour) with a heaviness in the chest or a feeling of sadness, or they experience difficulty falling asleep from worry. The prescription: go to bed early (by 10 PM) to consolidate the day's Yang before the dark hours; wake at sunrise and get direct morning light; and practice breathing exercises — the Lungs' function is dispersing and descending Qi, and conscious diaphragmatic breathing supports this. Autumn is the season to harvest: complete the tasks of the year, clear emotional and physical clutter, and practice 'letting go' rituals. For sleep specifically, the early-to-bed pattern of autumn is the training ground for winter's full dormancy. If you can master the rooster schedule in October, the transition to winter's even earlier bedtime is seamless.
- The 'rooster rise' means getting morning sunlight within 30 minutes of waking — this anchors your circadian phase against the shortening photoperiod.
- Autumn early-morning waking (3-5 AM) is the Lung's signature. Address it with breathing practice and by releasing grief or worry during the day.
- Autumn is the ideal season to start a regular meditation or qigong practice — the Lungs benefit from slow, deep, rhythmic breathing.
"The three months of autumn are called the time of peace and calm. The weather turns cool, and the earth becomes clear. Go to rest early, rise early, rising with the rooster — this keeps the spirit calm and protects the Lungs."
Winter (Kidney Time): Early to Bed, Late to Rise, Conserve the Jing
Winter is the season of water and the Kidneys — of dormancy, storage, and conservation. The Suwen prescription is the longest sleep of the year: 'rest early, rise late, rising with the sun, in the manner of the dormant will.' In winter, the ancient Chinese slept roughly 1-2 hours more than in summer, going to bed early and waking late — but note the crucial detail: 'rising with the sun,' not 'rising as late as possible.' Even in winter, the wake time is anchored to daylight. The winter sleep pattern is driven by the Kidneys, which store the Jing — the deepest reserve of vitality inherited from your parents and accumulated through your life. Winter is when the Jing must be conserved, and sleep is its primary conservation mechanism. Modern sleep science concurs: the 2018 population study found winter total sleep time increased by roughly 30 minutes with later wake times, and melatonin secretion is measurably longer in winter. The winter signature sleep problem is Kidney Yang Deficiency (cold feet, frequent night waking to urinate, lower back ache, fatigue despite adequate sleep hours) and Kidney Yin Deficiency (night sweats, hot flushes at night, vivid or anxious dreams, dry mouth). The prescription: protect the evening — lights dim by 7 PM, screens off by 8 PM, bed by 9:30-10 PM; wake with the sun (or a sunrise-simulating alarm for the dark months); keep the bedroom cool (16-18°C) but use warm bedding; wear socks to bed if feet are cold; and reduce late-night fluid intake to prevent nocturia. Winter sleep is deep and long by design — resist the urge to 'catch up' on work or socializing during the dark hours. The dormant will is the model.
- Winter is the season to protect the Kidneys: reduce alcohol, avoid overexertion, and get to bed before 10 PM — Kidney hour is 5-7 PM peak, and the deepest rest consolidates Jing.
- If you wake to urinate 1-2 times nightly in winter, stop fluids after 7 PM and consider Kidney-tonifying foods (black beans, walnuts) in the evening meal.
- A sunrise alarm clock is the modern 'rise with the sun' — in deep winter, its gradual light ramp is superior to a sudden alarm for the Kidney-pattern sleeper.
"The three months of winter are called the time of closing and storing. Water freezes and the earth cracks open. Go to rest early, rise late, rising with the sun, in the manner of the dormant will — this is the way to store the Qi and conserve the Jing."
How to Transition Between Seasons: The 2-Week Adjustment Protocol
The most common mistake in seasonal sleep adjustment is attempting a sudden switch. You cannot move your bedtime by two hours in one night any more than you can instantly relocate your circadian rhythm — abrupt shifts produce jet-lag-like symptoms. The TCM approach is transitional, and I prescribe a structured 2-week protocol at each solstice and equinox. Week 1 — Assessment and light anchoring: keep your current schedule but add a fixed morning light exposure (15-30 minutes of outdoor light within 30 minutes of waking). Track your natural sleep propensity: note the time you feel sleepy at night and the time you naturally wake without an alarm. This gives you your current phase. Week 2 — The 15-minute rule: shift your bedtime and wake time by no more than 15 minutes every 3 days toward the seasonal target. Move the wake time first (light is the strongest phase-shifter), then the bedtime follows naturally. Pair each shift with light exposure at the new wake time and light avoidance (dimming) at the new bedtime. By the end of week 2, you will have shifted approximately 30-60 minutes — enough to align with the season. The full transition from summer to winter schedules typically requires repeating this protocol twice (a total of 4 weeks), which conveniently spans the autumn equinox to the first frost. Expect a brief adjustment dip: for 3-5 days after each 15-minute shift, sleep may feel slightly worse before it improves — this is the brain's phase-locking catching up. Do not retreat to your old schedule during this dip. Consistency is the entire game.
- Anchor every transition to the equinoxes and solstices — set calendar reminders for March 20, June 21, September 22, and December 21.
- The 15-minute-per-3-days rule applies to both directions. Shifting later (spring-to-summer) is easier than shifting earlier (autumn-to-winter), so be patient in September.
- During transition weeks, avoid caffeine after noon and alcohol entirely — both interfere with circadian phase-shifting.
- If you travel across time zones during a season change, adjust to the local sun before re-applying the seasonal protocol.
"The sage nourishes life by following the four seasons: spring and summer nourish Yang, autumn and winter nourish Yin. Thus he rises and rests with the turning of heaven and earth."
The Seasonal Sleep Schedule: A Practical Reference Table
Here is the complete seasonal sleep framework as a practical reference. These times assume a mid-latitude location (35-45°N) and a standard 10 PM-6 AM baseline; adjust ±30 minutes based on your latitude and chronotype. Spring (March-May): bedtime 10:30-11 PM, wake 6:30-7 AM (with sunrise), morning movement within 30 minutes of waking, sleep duration 7.5-8 hours, emphasis on gentle morning exercise to disperse Liver Qi. Summer (June-August): bedtime 11-11:30 PM, wake 6-6:30 AM, 15-30 minute siesta between 1-3 PM, sleep duration 7-7.5 hours total (including siesta), emphasis on keeping the bedroom cool and guarding against Heat disturbing the Shen. Autumn (September-November): bedtime 10-10:30 PM, wake 6-6:30 AM (with sunrise — the rooster rise), sleep duration 8 hours, emphasis on morning light anchoring and breathing practice to support the Lungs. Winter (December-February): bedtime 9:30-10 PM, wake 7-7:30 AM (with the sun or sunrise alarm), sleep duration 8.5-9 hours, emphasis on early light avoidance in the evening, warm feet, and Kidney conservation. The universal light rules across all seasons: get bright light within 30 minutes of waking (10-30 minutes, outdoor light preferred); dim lights to warm amber below 2700K by 2 hours before bedtime; and avoid screens in the final hour before bed. If you follow this table, you will sleep more in winter, less in summer, and in sync with the sun year-round — exactly as the Yellow Emperor prescribed, and exactly as your melatonin curve intends.
- Chronotypes shift the times but not the relative pattern: a night owl's summer bedtime may be midnight, and their winter bedtime 10:30 PM — the 90-minute seasonal swing remains.
- If your work schedule cannot accommodate seasonal wake times, prioritize the seasonal bedtime and use morning light exposure to anchor your phase.
- Track your seasonal sleep in a journal for one full year — the data will convince you of the seasonal pattern more powerfully than any ancient text.
"Those who follow the four seasons are free of disease; those who oppose them are struck down by illness. This is the way of heaven, and the sage obeys it."