Calidad de la evidencia 4.63/5
Puntuación de revisión en ocho dimensiones según la rúbrica de calidad . Cada dimensión puntuada de 1 a 5.
- D1 Anclaje en las fuentes
- 4/5
- D2 Autoridad de las fuentes
- 5/5
- D3 Aritmética
- 5/5
- D4 Incertidumbre
- 4/5
- D5 Alcance
- 5/5
- D6 Prosa
- 5/5
- D7 Honestidad sobre la percepción
- 4/5
- D8 Completitud de las advertencias
- 5/5
Cómo varía el riesgo
La cifra principal promedia situaciones muy diferentes. Así es como varía la probabilidad según el escenario o el contexto:
1 de cada 1.000.000
No cohort has measured a respiratory-infection rate attributable to this scenario. Without an underlying viral exposure, cold feet on tile do not produce a cold. Point estimate is a structural "effectively zero" placeholder, not a measured rate.
1 de cada 7,1 · 14%
Matches the Eccles 2005 arm: ~14% self-reported cold symptoms within 4–5 days after a 20-minute cold-foot immersion vs ~6% in controls. This is a symptom-conversion rate in an already-exposed population under a severe chilling protocol, not an infection rate from going sockless at home.
1 de cada 20 · 5,0%
Very rough. Order of magnitude derived from WHO cold-housing guidance and UK excess-winter-mortality attribution (~21.5% of ~20,000–50,000 annual excess winter deaths → cold homes, concentrated in over-65s). The dominant pathways are cardiovascular and respiratory, not viral infection. Included as the subgroup the folk warning might actually apply to, even though it is almost never the one a grandmother has in mind when telling a child to put on slippers.
1 de cada 2,0 · 50%
For someone with a cold-triggered vascular or cardiac condition, bare feet on cold tile reliably produces the trigger (Raynaud's episode, anginal chest pain) — but this is the underlying condition expressing itself, not a new illness. Included only to flag that "cold feet cause real symptoms" is true in this subgroup without rescuing the viral- infection folk model.
La longitud y el tono de la barra clasifican estos escenarios entre sí, no frente a otros riesgos. Las probabilidades exactas se muestran junto a cada uno.
La creencia popular de que caminar por una casa con calefacción sin zapatillas, calcetines o un suéter provoca un resfriado es mecánicamente incorrecta en la forma en que se suele expresar, y modestamente correcta en una forma mucho más estrecha de lo que la gente que la transmite suele querer decir. Los resfriados son causados por virus (el CDC cifra el número en más de 200 virus respiratorios distintos, siendo los rinovirus los más comunes), y se transmiten por gotitas y contacto, no por la temperatura. Sin una exposición viral subyacente, los pies descalzos sobre baldosas producen pies fríos y nada más. La parte del modelo popular que sobrevive al contacto con la evidencia es más estrecha: Johnson y Eccles (Cardiff, 2005) demostraron en un ensayo aleatorizado de 180 personas que una inmersión de 20 minutos de los pies en frío elevó los síntomas de resfriado autoinformados durante los siguientes 4–5 días del 6% al 14%, y Foxman et al. (PNAS, 2015) demostraron que el rinovirus se replica mejor y la respuesta innata de interferón es más débil a los 33–35 °C más fríos de la cavidad nasal que a 37 °C. Esos dos resultados juntos apoyan una única afirmación específica: el enfriamiento puede convertir un portador viral subclínico en un resfriado sintomático. No apoyan la afirmación de que la exposición al frío produce enfermedades de la nada.
Lo interesante de este miedo particular es la brecha entre el escenario que nombra y el escenario donde el frío en el hogar realmente mata a las personas. La advertencia popular se suele dar a un niño o adulto sano en una casa con calefacción (ponte zapatillas, no te sientes en baldosas frías, no camines con el pelo mojado), donde el efecto de modulación de Eccles es el límite de lo que la evidencia permite y ninguna cohorte ha intentado medir una tasa de infección por invierno atribuible a ello. El escenario donde el frío interior es inequívocamente letal es casi el demográfico opuesto: residentes ancianos frágiles en hogares mantenidos por debajo de 16–18 °C, donde las Guías de Vivienda y Salud de la OMS de 2018 y los datos de mortalidad invernal excesiva de la ONS del Reino Unido identifican algo así como el 21.5% de 20,000–50,000 muertes invernales excesivas anuales como atribuibles a viviendas frías, siendo las enfermedades circulatorias y respiratorias las causas dominantes. Ese daño se trata de la temperatura ambiente de la habitación y el estrés vascular, no de olvidar los calcetines.
Donde el encuadre de “insignificante” no se aplica: cualquier persona con el fenómeno de Raynaud desencadenará de forma fiable un episodio por baldosas frías, independientemente de la infección, y la angina inducida por el frío es un evento cardíaco real para los susceptibles. Los lectores inmunocomprometidos que porten un virus respiratorio pueden estar más cerca del brazo del 14% de Eccles que de la línea de base de la población general, aunque el estudio no tuvo la potencia para afirmarlo. El subgrupo específico al que debería dirigirse la advertencia popular para que coincida con los datos de mortalidad por frío en el hogar (adultos mayores frágiles y bebés en viviendas con calefacción insuficiente, especialmente con enfermedades cardiorrespiratorias existentes) no suele ser el subgrupo que realmente recibe la advertencia. El consejo de las zapatillas es en su mayoría el instinto cultural correcto apuntado a la exposición equivocada.
Datos curiosos relacionados
Caminar bajo la lluvia no te dara un resfriado. Sentarse en superficies frias no causara infecciones de vejiga. Estar poco abrigado no te enfermara. Los virus causan infecciones. La temperatura no.
Registro de evidencia
Cada número a continuación es lo que reportó cada fuente, con la cita textual en la que nos basamos y cómo llegamos a nuestra cifra. Haz clic en cualquier enlace para verificarlo directamente.
2/5 fuentes verificadas de forma independiente palabra por palabra frente a la fuente citada
-
[1] Family Practice (Oxford Academic), via PubMed — Acute cooling of the feet and the onset of common cold symptoms
Acute cooling of the feet and the onset of common cold symptomsSee all 3 Likelier entries citing this source →
- Estadística
13/90 chilled subjects vs 5/90 controls self-reported cold symptoms in the 4–5 days after a 20-minute cold-foot immersion (P=0.047)- Extracto
“"There is a common folklore that chilling of the body surface causes the development of common cold symptoms, but previous clinical research has failed to demonstrate any effect of cold exposure on susceptibility to infection with common cold viruses. [...] 13/90 subjects who were chilled reported they were suffering from a cold in the 4/5 days after the procedure compared to 5/90 control subjects (P=0.047). [...] Acute chilling of the feet causes the onset of common cold symptoms in around 10% of subjects who are chilled. Further studies are needed to determine the relationship of symptom generation to any respiratory infection." ”
- Datos de la fuente de
- 2005-12-01
- Accedido
- 2026-04-16 · copia archivada
- Cálculo
- This is the canonical trial behind any "cold feet causes colds" claim. Critical qualifier the authors themselves flag: the study measured self-reported symptoms, not laboratory-confirmed new infections. The plausible mechanism the authors propose is that reflex vasoconstriction in the upper airway on cold- foot exposure reduces mucosal blood flow and temporarily lowers local defences — converting a pre-existing subclinical carriage of rhinovirus or another respiratory virus into a symptomatic cold. That is a modulation effect, not a causation effect. Without an underlying viral exposure, cooling the feet is not expected to produce illness from nothing. 90 subjects per arm gives an absolute difference of 8 percentage points (14% vs 6%); the confidence bound is wide, and no replication of comparable rigour exists at the scale needed to attach a per-winter probability to "no slippers at home."
- Independencia
- Independent single-centre RCT at Cardiff (Common Cold Centre); editorially independent of the CDC and WHO sources. The Foxman 2015 mechanistic paper below provides a biological model compatible with Eccles' clinical result but was conducted in a separate lab with different methodology (mouse airway cells, not human subjects).
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[2] Proceedings of the National Academy of Sciences (PNAS), via PubMed — Temperature-dependent innate defense against the common cold virus limits viral replication at warm temperature in mouse airway cells Verificado
Temperature-dependent innate defense against the common cold virus limits viral replication at warm temperature in mouse airway cellsSee all 2 Likelier entries citing this source →
- Estadística
Rhinovirus replicates more robustly at 33–35 °C (nasal cavity) than at 37 °C (core body), with weaker interferon/antiviral response at the cooler temperature- Extracto
“"Most isolates of human rhinovirus, the common cold virus, replicate more robustly at the cool temperatures found in the nasal cavity (33–35 °C) than at core body temperature (37 °C). [...] These findings demonstrate that in mouse airway cells, rhinovirus replicates preferentially at nasal cavity temperature due, in part, to a less efficient antiviral defense response of infected cells at cool temperature." ”
- Datos de la fuente de
- 2015-01-20
- Accedido
- 2026-04-16 · copia archivada
- Verificación
- Extracto recuperado de forma independiente y confirmado palabra por palabra frente a la fuente citada durante nuestra auditoría de fundamentación.
- Cálculo
- Foxman et al. supplies the cleanest known mechanism for any cold-exposure- to-cold-illness signal: rhinovirus itself replicates better in a cooler nose, and the innate interferon response is weaker at 33 °C than at 37 °C. This makes Eccles' symptom-onset result biologically plausible without rescuing the folk model. The study is mouse airway cells in vitro, not an epidemiological measurement, and no study has translated the temperature- dependent replication curve into a per-exposure infection probability for a human wearing socks versus going barefoot. The mechanism is real; the epidemiological effect size at normal indoor conditions is not quantified.
- Independencia
- Yale laboratory study with no authorship, funding, or institutional overlap with the Cardiff Eccles group; treat as methodologically independent mechanistic corroboration. Independent of the CDC and WHO sources.
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[3] US Centers for Disease Control and Prevention — About the Common Cold
About the Common ColdSee all 2 Likelier entries citing this source →
- Estadística
More than 200 respiratory viruses cause colds; rhinoviruses are the most frequent cause; primary spread is droplets and contact- Extracto
“"More than 200 respiratory viruses can cause colds. Rhinoviruses are the most frequent cause of colds in the United States. [...] Most respiratory viruses are spread through droplets that an infected person releases when they cough or sneeze. These droplets can enter your body if you breathe them in or touch a contaminated surface and then touch your eyes, nose, or mouth." ”
- Datos de la fuente de
- 2026-02-19
- Accedido
- 2026-04-16 · copia archivada
- Cálculo
- CDC's current patient-facing page is the plain-language anchor for the "colds are viral, not thermal" frame. The folk model treats cold exposure as causative; CDC treats virus exposure as causative and does not list chilling or being under-dressed indoors as a transmission route at all. The Eccles and Foxman results sit downstream of this: you still need the virus. Without rhinovirus or one of the other ~200 candidates in your airway, cold feet on tile do not produce a cold.
- Independencia
- Institutional CDC public-health guidance; editorially independent of the Eccles clinical trial and Foxman mechanistic paper, though it aligns with both.
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[4] World Health Organization (via NCBI Bookshelf) — Low indoor temperatures and insulation — WHO Housing and Health Guidelines Verificado
Low indoor temperatures and insulation — WHO Housing and Health Guidelines- Estadística
WHO recommends minimum indoor temperature of 18 °C to protect general populations; higher minimum for vulnerable groups (older people, children, chronic cardiorespiratory illness)- Extracto
“"For countries with temperate or colder climates, 18 °C has been proposed as a safe and well-balanced indoor temperature to protect the health of general populations during cold seasons. [...] A higher minimum indoor temperature than 18 °C may be necessary for vulnerable groups including older people, children and those with chronic illnesses, particularly cardiorespiratory disease." ”
- Datos de la fuente de
- 2018-11-27
- Accedido
- 2026-04-16 · copia archivada
- Verificación
- Extracto recuperado de forma independiente y confirmado palabra por palabra frente a la fuente citada durante nuestra auditoría de fundamentación.
- Cálculo
- WHO's guideline is the authoritative carve-out for the one scenario in which "being under-dressed at home" really does kill people: under-heated housing in cold climates, especially for the elderly and those with cardiorespiratory disease. The exposure here is the ambient indoor temperature (below ~18 °C sustained), not a barefoot afternoon in a heated 21 °C living room. The outcome is cardiovascular and respiratory morbidity and mortality, not the common cold. This is the reason the headline framing ("folk belief overrated") must be paired with an explicit vulnerable-group caveat rather than a blanket dismissal.
- Independencia
- WHO expert consensus guideline synthesising the cold-housing evidence base. Editorially independent of the Eccles, Foxman, and CDC sources and addresses a distinct exposure-outcome pair (sustained low ambient temperature → cardiovascular/respiratory death), not symptom onset of the common cold.
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[5] UK Parliamentary Office of Science and Technology — Winter mortality (POSTnote 752)
Winter mortality (POSTnote 752)- Estadística
Excess winter deaths in England and Wales ranged ~20,000–50,000/year 2000–2019; ~21.5% of excess winter deaths attributable to cold homes; most deaths from circulatory or respiratory disease among the elderly- Extracto
“"Between 2000 and 2019, excess winter deaths ranged from 20,000 to 50,000 a year [...] Most excess winter deaths are due to circulatory or respiratory diseases and the majority occur amongst the elderly population. [...] It has been estimated that 10% of excess winter deaths are attributable to fuel poverty and 21.5% to cold homes." ”
- Datos de la fuente de
- 2024-01-01
- Accedido
- 2026-04-16 · copia archivada
- Cálculo
- This is the population-scale number for the one real cold-in-the-home harm: under-heated housing kills elderly people through cardiovascular and respiratory pathways, not through infection. It does not apply to the folk-belief scenario (healthy adult, barefoot in a warm house) and should not be aggregated with the Eccles symptom-onset figure. Used here only to bound the vulnerable-group subgroup in the regional breakdown and to keep the caveats honest about who the folk warning, repurposed, actually applies to.
- Independencia
- UK Parliament research briefing drawing on ONS winter-mortality data and NICE fuel-poverty reviews. Editorially independent of the WHO guideline (though it references the same underlying epidemiology) and independent of the Eccles, Foxman, and CDC sources.