Seasonal Adaptation

In 1969, twelve men lived at a British Antarctic base after seventeen weeks of complete isolation. On the 9th and 10th of July the temperature fell from just above freezing to minus 24°C in a day. On the 14th, eight of the twelve fell ill with colds. The investigators went looking for a source and this lesson leaves that question alone. What they wrote down with care was the weather. The autumn does the same thing to all of us more slowly: the atmosphere changes on several levels at once, and the body changes with it. How well it manages depends on the terrain it starts from.

The atmosphere changes on several levels at once

Days shorten, so light, melatonin and vitamin D shift. The temperature falls and the air gets drier: in a small study of eleven healthy people, nasal mucus took 18.5 minutes to cross the nose on dry air against 11.9 minutes on room air (Salah et al., 1988). The outside air also gets dirtier. Heating adds smoke, and winter temperature inversions trap fine particles close to the ground.

There is one more level, and it needs to be handled carefully. Geomagnetic disturbances peak around the equinoxes. That has been known since Sabine in 1856 and was explained by Russell and McPherron in 1973. A direct link between that peak and the common cold has not been shown. It belongs in this list for one reason: the body is receiving new conditions from many directions in the same weeks.

The body changes with it

Dopico and colleagues (Nature Communications, 2015) measured gene expression in blood and fat tissue across several populations. More than 4,000 protein-coding genes follow a seasonal pattern. In the European winter the immune system shows a markedly pro-inflammatory profile, with higher levels of the soluble IL-6 receptor and C-reactive protein. In Oceania the pattern is reversed, so it follows the season and not the calendar. Whatever the body does in autumn, it is a preparation that is built into it.

The cleaning system slows down in the cold

The mucus in the nose and airways is the body's own clearing system: cilia move it along, it takes particles with it, and it carries them away. Cold, dry air makes that system slower, and the system costs more energy to run. Cold also works from the outside in. In a 2005 trial by Johnson and Eccles (Family Practice), 180 healthy volunteers either soaked their feet in ice water for twenty minutes or went through a control procedure. Within four to five days, 13 of 90 chilled volunteers reported a cold against 5 of 90 controls (p = 0.047). That is a modest effect, and older experiments in which volunteers were chilled after being exposed on purpose found nothing, so it is one study. Eccles's own explanation is a reflex narrowing of blood vessels in the nose that dampens its defences. The delay matches the Antarctic one: about four days.

"Acute chilling of the feet causes the onset of common cold symptoms in around 10% of subjects who are chilled." Johnson C, Eccles R. "Acute cooling of the feet and the onset of common cold symptoms." Family Practice 2005;22(6):608–613.

Same exposure, different outcome

In two studies from Carnegie Mellon, every volunteer received the same dose of exposure. What differed was how they slept. In Cohen's 2009 study, people sleeping under seven hours had 2.94 times the risk of developing a cold compared with those sleeping eight hours or more, and people with poor sleep efficiency had an odds ratio of 5.5. In Prather's 2015 study, with sleep measured by wrist sensors, five to six hours of sleep carried about four times the risk of seven hours or more. Short sleep predicted the outcome better than age, stress, smoking, income or education.

That is the terrain argument in its cleanest form, and it needs no claim about causes: the same exposure produces a different result depending on the state of the body that meets it. Vitamin D shows the same pattern. In a large analysis of 25 trials (Martineau et al., BMJ 2017) supplementation lowered the risk of respiratory infections overall (odds ratio 0.88), and far more in people who started with a deficiency (odds ratio 0.30). As data about terrain, it says that daylight and status matter. We do not use it here as advice to supplement.

What is proven, and what is model

Proven or well established: the body changes with the season; cold, dry air slows nasal clearing; chilling can bring on symptoms in some people; most cold symptoms come from the body's own response; short sleep strongly raises the risk; winter air is dirtier.

Model, not proven: that a low cell voltage or a high toxic load makes the body trigger that response more easily, and that the illness is therefore a clean-up. The idea has deep roots in terrain thinking. It also has no direct evidence. Tennant's voltage figures (−20 to −25 mV) come from skin and meridian measurements and are not the same scale as the membrane potential of a cell (−40 to −90 mV) or of a mitochondrion (−140 to −180 mV), so no single number should be treated as the cause. What does hold up conceptually is that cells, including immune cells, lose function when they lose their polarisation. General "detox" has little scientific support either: apart from specific poisonings such as lead or arsenic, no general phenomenon of toxification has been demonstrated. We therefore present this as a model that fits the proven pieces, and we say where it ends.

First: prevent

Then: the first 24 hours

The trigger is usually ordinary: a day dressed too thin, a night too short, a long evening in the cold. When the first signal comes (a scratch in the throat, a heavy head, a chill you cannot shake), act the same day. Warm. Salt. Rest.

Warm drinks. In 30 people with colds (Sanu & Eccles, Rhinology 2008), a hot drink gave immediate and lasting relief of runny nose, cough, sneezing, sore throat, chilliness and tiredness, and the same drink at room temperature helped only some of those. It did not change objective airflow. It changed how people felt, and that counts.

Hot soup. My own routine is a salted vegetable soup: leek, celery, carrot, onion, celeriac, bay leaf, pepper and Celtic salt, with the vegetables eaten as well. Celtic salt contains more minerals than table salt (around 0.58 g magnesium per 100 g by producer figures), although a bowl gives only a small amount, about 17 mg magnesium from 3 g of salt. I will not claim more for it than that. Chicken soup has been studied slightly more. In 1978 hot chicken soup moved nasal mucus a little faster than hot water (15 subjects), and in a laboratory study (Rennard, Chest 2000) chicken soup inhibited migration of inflammatory cells. In the same study, each of the vegetables inhibited it on its own too. Nobody has compared chicken soup with vegetable soup, so there is no basis for saying one is better. What the evidence supports is warm, salty and full of vegetables, and that is also what experience says.

Salt water. In a small open pilot in Edinburgh (Ramalingam 2019), rinsing the nose and gargling with hypertonic saline shortened symptoms by about two to two and a half days. It is a pilot with no blinding. It fits Satomura's result.

Tea by day. Our Cold mix is for the daytime: black tea, turmeric, ginger, cardamom, cinnamon, thyme, peppermint, star anise, sage, clove and black pepper (one teaspoon per 250 ml, 100°C, seven to ten minutes; it contains caffeine). The best-supported part of it is that it is hot. Thyme has trial evidence for cough, mostly in fixed combinations with primrose root for acute bronchitis. Peppermint's menthol gives a feeling of easier breathing, but it does not measurably reduce nasal resistance in a cold. For ginger, turmeric, cinnamon and clove I found no convincing clinical evidence in colds, only laboratory data and tradition. Echinacea, which is in many cold teas, has no convincing evidence in the Cochrane review of 24 trials (2014). We say so.

Do not fast by reflex. In mice (Wang & Medzhitov, Cell 2016), feeding helped in viral inflammation and hurt in bacterial inflammation, with glucose as the switch. Not eating is not universally right or wrong.

Application

This lesson ends on the fifth rung. Understanding the season is the fourth. Applying it is what decides the outcome: the early night, the extra layer, the warm soup on the evening the throat scratches. Nothing here needs a prescription, and almost nothing here needs money.

What this lesson does not claim

It does not claim that the common cold is a proven detox, that one voltage number is the cause, that the equinox peak causes colds, that chicken soup beats vegetable soup, or that any tea cures a cold. It claims that the body responds to the season, that sleep, warmth and humidity change how it responds, and that acting early with warmth, salt and rest is cheap and sensible. If someone points out that colds also peak when school restarts in September, that is a fair point about contact, and it is a separate question from the one this lesson asks.

Sources

1. Allen TR, Bradburne AF, Stott EJ, Goodwin CS, Tyrrell DAJ. "An outbreak of common colds at an Antarctic base after seventeen weeks of complete isolation." Journal of Hygiene 1973;71:657–667.
2. Dopico XC, et al. "Widespread seasonal gene expression reveals annual differences in human immunity and physiology." Nature Communications 2015;6:7000.
3. Salah B, Dinh Xuan AT, Fouilladieu JL, Lockhart A, Regnard J. "Nasal mucociliary transport in healthy subjects is slower when breathing dry air." European Respiratory Journal 1988.
4. Johnson C, Eccles R. "Acute cooling of the feet and the onset of common cold symptoms." Family Practice 2005;22(6):608–613.
5. Cohen S, Doyle WJ, Alper CM, Janicki-Deverts D, Turner RB. "Sleep habits and susceptibility to the common cold." Archives of Internal Medicine 2009;169(1):62–67.
6. Prather AA, Janicki-Deverts D, Hall MH, Cohen S. "Behaviorally assessed sleep and susceptibility to the common cold." Sleep 2015;38(9):1353–1359.
7. Martineau AR, et al. "Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data." BMJ 2017;356:i6583.
8. Satomura K, et al. "Prevention of upper respiratory tract infections by gargling: a randomized trial." American Journal of Preventive Medicine 2005. PMID 16242593.
9. Sanu A, Eccles R. "The effects of a hot drink on nasal airflow and symptoms of common cold and flu." Rhinology 2008;46(4):271–275. PMID 19145994.
10. Saketkhoo K, Januszkiewicz A, Sackner MA. "Effects of drinking hot water, cold water, and chicken soup on nasal mucus velocity and nasal airflow resistance." Chest 1978;74:408–410. PMID 359266.
11. Rennard BO, et al. "Chicken soup inhibits neutrophil chemotaxis in vitro." Chest 2000;118:1150–1157.
12. Ramalingam S, et al. Hypertonic saline nasal irrigation and gargling in the common cold (ELVIS pilot trial). Scientific Reports 2019.
13. Karsch-Völk M, et al. "Echinacea for preventing and treating the common cold." Cochrane Database of Systematic Reviews 2014.
14. Wang A, Huen SC, Luan HH, et al. "Opposing effects of fasting metabolism on tissue tolerance in bacterial and viral inflammation." Cell 2016;166:1512–1525.
15. Russell CT, McPherron RL. "Semiannual variation of geomagnetic activity." Journal of Geophysical Research 1973;78:92–108.
16. Own databases: Kruidenvinder.xlsx (InfusionTea: Cold, Wintertea); terrain notes on Tennant, Becker and the Antarctic outbreak.