Guide: Vivre avec les quatre saisons

Across nearly 250,000 people, blood pressure, cholesterol and waistlines all sat higher in the cold months than in summer. The body runs on a yearly cycle, and classical Chinese medicine built a way of living around that cycle centuries before anyone measured it.

The Classical Frame

春夏養陽，秋冬養陰 (chūn xià yǎng yáng, qiū dōng yǎng yīn): nourish yang in spring and summer, nourish yin in autumn and winter. (Huangdi Neijing, Su Wen, chapter 2, "The Great Treatise on Attuning the Spirit to the Four Seasons.")

Classical Chinese medicine works with five seasons, not four. The Five Elements pair with them in a fixed order, and that pairing is where the counsel for each part of the year comes from. Spring belongs to Wood and the Liver, its character upward and outward. Summer belongs to Fire and the Heart, the season of maximum yang. Between summer and autumn sits a fifth season, late summer, belonging to Earth and the Spleen and tied to digestion. Autumn belongs to Metal and the Lung, the turn toward conserving. Winter belongs to Water and the Kidney, the season of storage, when the body banks the deep essence it will spend come spring.

What Modern Biology Shows

The Research & Studies

Everything here is based on the research we have collected and checked, sorted into groups and ordered with the strongest evidence first. Click any claim to open the studies behind it.

Heart And Vascular

Blood pressure runs about 3 mmHg higher in winter than summerModerate · risk

In plain terms

Blood pressure, cholesterol and waistlines tend to run a little higher in winter than in summer. Across nearly a quarter of a million people, winter blood pressure was about 3 points higher on the top number, which is part of why heart trouble clusters in the cold months.

In detail

In a pooled cross-sectional analysis of 237,979 participants from 24 studies across 15 countries, cardiovascular risk factors showed a consistent seasonal pattern of higher levels in winter and lower in summer, in both hemispheres. The northern-hemisphere winter-to-summer differences were 2.9 mmHg systolic and 1.4 mmHg diastolic blood pressure, 0.26 kg/m2 body-mass index, 0.24 inches (0.6 cm) waist circumference, 3.9 mg/dL (0.10 mmol/L) total cholesterol, 4.3 mg/dL (0.11 mmol/L) LDL cholesterol and 1.3 mg/dL (0.07 mmol/L) glucose. Because it compares different people measured in different seasons, not following individuals, it describes a population pattern, not proving that season drives an individual's numbers.

How to use it

Winter is the season to hold the line on the ordinary levers, not let them slip: keep moving on the cold, dark days, keep meals steady, and if your blood pressure is monitored, expect it to read a touch higher in the cold and read the trend across the year, not a single winter measurement.

The study · 1

Marti-Soler et al., seasonality of cardiovascular risk factors across 15 countries · Heart 2014;100(19):1517-23

Daylight and temperature move blood pressure as two independent signalsEmerging · mixed

In plain terms

Blood pressure does not only follow the cold; it also follows the length of the day. In people wearing temperature sensors, warmer skin temperature came with lower daytime pressure, and longer daylight hours came with different night-time and early-morning pressure, with temperature and daylight each mattering on their own.

In detail

In 1,897 patients who wore personal environmental-temperature loggers during 24-hour ambulatory blood-pressure monitoring, multivariate models adjusting for age, sex, body-mass, treatment and daylight hours found daytime systolic pressure negatively related to personal temperature (-0.14 mmHg per unit; 95% CI -0.25 to -0.02), night-time pressure positively related to daylight hours (0.63; 0.37 to 0.90) and the morning surge negatively related to daylight hours (-0.54; -0.87 to -0.21). The authors concluded that personal temperature and seasonality, expressed as daylight hours, are two independent predictors of ambulatory blood pressure. It is observational, so it establishes association, not cause.

How to use it

This is the measurable core of what the tradition means by living with the light: daylight length has a real physiological signature. Treat it as one more reason to get outdoor light through the year, and, if you track blood pressure, to expect seasonal drift, not a fixed number.

The study · 1

Modesti et al., seasonal blood-pressure changes track temperature and daylight hours independently · Hypertension 2013;61(4):908-14

Mood & stress

Bright light lifts winter depression, with about 40% more people respondingModerate

In plain terms

For winter depression, sitting in front of a bright light box most mornings helps more than a dummy light. In pooled trials, people were about 40% more likely to respond, a small-to-medium benefit that points clearly in one direction.

In detail

This meta-analysis pooled 19 randomized controlled trials of bright light therapy for seasonal affective disorder, with 610 patients contributing depression-rating data and 559 contributing response data. Bright light was superior to placebo with a standardized mean difference of -0.37 (95% CI -0.63 to -0.12) on depression ratings and a risk ratio of 1.42 (95% CI 1.08 to 1.85) for treatment response. The authors noted moderate heterogeneity, small-to-medium sample sizes and moderate-to-high risk of bias, and called for larger high-quality trials, which is why the finding sits at moderate, not strong.

How to use it

If your mood drops through the dark months, a morning bright-light routine is the best-tested first step and it costs little to try. Use it early in the day for the timing to line up with your body clock, and treat it as a seasonal tool you begin as the nights draw in, not something to start once winter has fully set in.

The study · 1

Pjrek et al., efficacy of light therapy in seasonal affective disorder, meta-analysis of RCTs · Psychother Psychosom 2020;89(1):17-24

Sleep

Winter sleep runs up to 60 minutes longer, with about 30 minutes more REMEmerging · mixed

In plain terms

People tend to sleep a bit longer and get more dream (REM) sleep in winter than in spring or summer. In a year-long clinic study, winter sleep ran up to an hour longer, though only the REM and deep-sleep changes were statistically solid.

In detail

In a retrospective analysis of three-night polysomnography from a Berlin neuropsychiatric sleep clinic, 188 patients (mean age 46.6, 52% female, seen for insomnia, depression or breathing disorders) were averaged by month across the year. Total sleep time was up to 60 minutes longer in winter than summer but not statistically significant; REM sleep was about 30 minutes longer in winter than spring (p = 0.009, about 5% of total sleep time, p = 0.011); REM latency was about 25 minutes shorter in autumn than spring (p = 0.010); and slow-wave (deep) sleep was 30 to 50 minutes shorter in autumn, significant as a percentage of total sleep (a roughly 10% relative drop, p = 0.017). The sample was clinical, not healthy, so the effect in untroubled sleepers is not established.

Who this may not transfer to:Measured in adults already seeking help for disturbed sleep, so the size of the seasonal shift in healthy sleepers is not established here.

How to use it

Take it as permission to let winter sleep be longer, not fighting it back to a summer schedule. If your rest worsens in the dark months rather than simply lengthening, that is the point to work on light timing and the steps in the insomnia guide.

The study · 1

Seidler et al., seasonality of human sleep from clinic polysomnography · Front Neurosci 2023;17:1105233

Four findings stand out:

• Winter is the higher-risk cardiovascular season. A pooled study of nearly 250,000 people found cholesterol, waistlines and blood pressure all above their summer levels. Cold-month habits push the same way: less activity, heavier meals, more time indoors.
• Daylight length follows blood pressure more closely than temperature does, across the same 15-country group.
• Winter sleep runs longer and holds more dream (REM) sleep, tracked in adults across a full 12 months.
• For people whose mood drops in the dark months, roughly 40 percent more responded to morning bright light than to a dummy light.

Where the Two Lenses Meet

Human physiology is seasonal, measured and confirmed. The timetable that assigns each season an organ is a frame for arranging attention through the year. Daylight is the reliable signal; treat the classical schedule as a lens on it.

Circadian entrainment is the shared mechanism. Daylight sets the body clock, and blood pressure, sleep and mood all follow that one yearly signal.

The element-and-organ pairings are a way of organizing attention. No study has measured them as a schedule the body keeps.

The tradition reached this picture by watching the year for centuries. Modern research, starting from measurement, keeps landing in the same place, the body clock, blood pressure, and sleep and mood all moving with the light.

Living With the Seasons

Spring: come out of winter gradually. Move your mornings earlier, loosen up with mobility work and walking outdoors, and take a daily dose of morning light to meet the lengthening day.

Summer: use the long evenings for activity and company. Stay ahead on fluids, and stay in tune with your own tolerance for heat.

Late summer: keep an unhurried pace, and take a short walk after eating to steady digestion.

Autumn: start moving your bedtime earlier, and get deliberate about evening light and screens before the dark months arrive.

Winter: give yourself more sleep and keep warm, and lean on morning light, the most useful winter habit on this site. If your mood drops through the dark months, the depression guide lays out the bright-light routine. If winter unsettles your sleep instead of lengthening it, start with sleep regularity and steady light timing.

Pick one adjustment for the season you are in, and let it settle before adding another, the way what to do first suggests for any change.

Go Deeper

• Yang Sheng, the fuller art of nourishing life across the day and the year.
• Morning light, the winter mood-and-clock lever.
• Circadian entrainment, how daylight sets the body clock.
• Sleep regularity: steadying sleep when the season disrupts it.
• Depression, the seasonal-mood guide and its light routine.
• Hypertension: winter blood pressure in depth.

Common Questions

Is there anything to seasonal eating?

Yes, in the ordinary sense, even without a trial to prove it. Western research has not run a clean study of seasonal eating as such, so it stands as sound traditional practice that also fits modern nutrition. Build meals around whole food and let what is fresh and local shape them. The classical pattern runs lighter and fresher in spring, cooling and watery in summer, and simple and warm through late summer to protect digestion. In autumn it turns moistening against the dry air, and in winter warming and nourishing with roots, broths and stews.

Why is blood pressure higher in winter?

Across 237,979 people, winter blood pressure ran about 2.9 mmHg higher on the top (systolic) number than in summer, with cholesterol and waistlines a little higher too. Part of it is behavior: less activity, heavier eating, more time indoors. Because cold pushes blood pressure up, keeping warm and holding the basics (movement, steady meals) matters more in winter than in summer.

Do we really sleep more in winter?

In a year-long clinic study of 188 adults, winter total sleep ran up to 60 minutes longer than summer, though that gap did not reach statistical significance. Dream (REM) sleep was the reliable part: about 30 minutes longer in winter than spring. The people studied were already seeking help for disturbed sleep, so the size of the shift in untroubled sleepers is not settled.

Does winter light help mood?

For seasonal affective disorder, pooling 19 randomized trials with 610 patients, morning bright light beat a dummy light on depression ratings (risk ratio 1.42). It is the best-tested first step and costs little to try. Use it early in the day, and start it as the nights begin drawing in, before winter has fully set in. If your mood drops each dark season, the depression guide has the full routine.

What does Chinese medicine say about the seasons?

Classical medicine treats the seasons as one piece of a larger daily practice it calls nourishing life. For that fuller art, the everyday habits of tending your vitality, see Yang Sheng.