We Run Ultras

(15) Winter Running Kit Must Work When You Stop

By Francesco//7 min read/Race execution & strategy

Plan for the slowest plausible part

Winter running clothing should protect you during the slowest plausible part of the outing, including an unexpected stop. Feeling comfortably warm while climbing does not establish that the same outfit will protect you while waiting, navigating or walking with an injured companion. The relevant balance is heat production against heat loss, and your running speed controls only part of it.

The ACSM cold-exercise consensus and physiological reviews by Castellani, Young and Stocks describe the interaction between work rate, insulation and environmental exposure. Gatterer's sport review, Castellani and Tipton's performance synthesis, and Fudge's clinical screening guidance add the importance of individual susceptibility and preparation. None supplies a universal air-temperature threshold for safe running in all conditions. [1–6]

Rain changes the calculation above freezing

Ito's 2013 experiment involved seven men running for 30 minutes at 5°C, with and without heavy simulated rain. Rain lowered measured skin and oesophageal temperatures while increasing oxygen consumption. His later study in 12 men found greater cold and metabolic strain during an hour of harder running in rain at the same air temperature. These are small chamber experiments, not forecasts of what every British winter run will do. They do establish that being above freezing does not make wet exposure physiologically trivial. [7–8]

Thompson and Hayward studied prolonged walking in cold, wind and heavy rain without protective rainwear. Responses varied greatly, and some participants became hypothermic. The ethically limited experiment cannot define a safe exposure duration. Its useful lesson is that continued movement does not guarantee adequate thermal protection when conditions and individual responses differ. [9]

Prior exertion can complicate the transition. Castellani observed greater subsequent cooling after exercise than after matched passive heating. Young's review describes possible impairment of cold defences with prolonged exertion, while Castellani's cold-strain study found that an index could miss differences after exhausting exercise. These findings argue against assuming that being fit, active or recently warm makes a forced stop harmless. [10–12]

More clothing can create another problem

The strongest counterargument to carrying substantial protection is that excessive insulation during hard running promotes sweating. That concern is legitimate. Holmér's experiments found that clothing insulation during exercise differed from standard manikin measurements, and Gavin's review emphasised clothing construction and the conditions of use. Fabric names alone cannot settle how a complete outfit will perform. [13–14]

Young's work on military protective clothing illustrates the transition particularly clearly: strenuous activity could accumulate sweat, compromising protection during later inactivity. Military ensembles differ substantially from running kit, so this is a mechanism to consider rather than a direct test of your jacket. Mäkinen's wind experiments likewise show that initial thermal state affects peripheral temperatures and sensations during subsequent exposure. [15–16]

The coaching implication is adjustable protection. Vent or remove appropriate layers before sustained climbing leaves them unnecessarily saturated, while retaining accessible insulation and weather protection for the next exposed section. A waterproof shell and an insulating layer perform different jobs. Pack them where adding protection does not require emptying the bag in the rain.

Preserve the ability to use the kit

Hands and feet deserve attention beyond general comfort. Kuklane's review identifies moisture as an important influence on footwear insulation. Castellani's local-heating experiment demonstrates that cold-related changes in finger temperature can affect manual dexterity. It does not recommend a particular heated glove; it supports acting before ordinary tasks become difficult. [17–18]

Open a zip, use the phone and handle food during a sheltered rehearsal with the gloves you intend to wear. That is a practical equipment check, not an experiment requiring deliberate cold exposure. Keep spare protection dry. Our cold-ultra hydration article addresses the separate problem of making drinking accessible.

Responses also differ between people. Greenfield's review cautions against simple sex-based assumptions once body characteristics are considered. Yurkevicius describes habituation that can reduce cold sensation and some defensive responses. Feeling accustomed to winter is therefore an unreliable reason to reduce contingency protection. [19–20]

Change the plan before function deteriorates

ACSM's prevention guidance favours individual clothing requirements and assessment of changing conditions. Paal's hypothermia review and NHS guidance establish the more serious boundary: confusion, slurred speech and marked deterioration in a cold person need urgent attention. Suspected hypothermia requires emergency medical help, shelter and protection from further cooling. Do not prescribe a harder run as treatment. [21–23]

Read wind and precipitation alongside temperature; the Met Office's wind-chill explanation describes why moving air changes cooling. Mountain Rescue advises route planning, spare clothing, navigation equipment and a torch. In a British hill emergency, call 999, ask for Police, then Mountain Rescue. [24–25]

Before leaving, identify where the route becomes exposed, where you could shorten it and what you would put on if running stopped. Scale the contingency to the terrain and likely rescue delay. If your protection depends on maintaining race pace all the way home, change the kit or shorten the route.

Sources

Cold exposure and individual risk

  1. Castellani JW et al., "ACSM Expert Consensus Statement: Injury Prevention and Exercise Performance during Cold-Weather Exercise" https://pubmed.ncbi.nlm.nih.gov/34752434/

  2. Castellani JW et al., "Human physiological responses to cold exposure: Acute responses and acclimatization to prolonged exposure" https://pubmed.ncbi.nlm.nih.gov/26924539/

  3. Stocks JM et al., "Human physiological responses to cold exposure" https://pubmed.ncbi.nlm.nih.gov/15152898/

  4. Gatterer H et al., "Practicing Sport in Cold Environments: Practical Recommendations to Improve Sport Performance and Reduce Negative Health Outcomes" https://pubmed.ncbi.nlm.nih.gov/34574624/

  5. Castellani JW et al., "Cold Stress Effects on Exposure Tolerance and Exercise Performance" https://pubmed.ncbi.nlm.nih.gov/26756639/

  6. Fudge JR et al., "Medical Evaluation for Exposure Extremes: Cold" https://pubmed.ncbi.nlm.nih.gov/26340736/

Rain, exercise and fatigue

  1. Ito R et al., "Effects of rain on energy metabolism while running in a cold environment" https://pubmed.ncbi.nlm.nih.gov/23371827/

  2. Ito R et al., "Rain exacerbates cold and metabolic strain during high-intensity running" https://pubmed.ncbi.nlm.nih.gov/31694361/

  3. Thompson RL et al., "Wet-cold exposure and hypothermia: thermal and metabolic responses to prolonged exercise in rain" https://pubmed.ncbi.nlm.nih.gov/8889744/

  4. Castellani JW et al., "Thermoregulation during cold exposure: effects of prior exercise" https://pubmed.ncbi.nlm.nih.gov/10409582/

  5. Young AJ et al., "Exertional fatigue and cold exposure: mechanisms of hiker's hypothermia" https://pubmed.ncbi.nlm.nih.gov/17622297/

  6. Castellani JW et al., "Cold strain index applied to exercising men in cold-wet conditions" https://pubmed.ncbi.nlm.nih.gov/11705759/

Clothing and wind

  1. Holmér I et al., "Resultant clothing insulation during exercise in the cold" https://pubmed.ncbi.nlm.nih.gov/1811589/

  2. Gavin TP, "Clothing and thermoregulation during exercise" https://pubmed.ncbi.nlm.nih.gov/14606923/

  3. Young AJ et al., "Physiological problems associated with wearing NBC protective clothing during cold weather" https://pubmed.ncbi.nlm.nih.gov/10685594/

  4. Mäkinen T et al., "Thermal responses to cold wind of thermoneutral and cooled subjects" https://pubmed.ncbi.nlm.nih.gov/10751101/

Extremities, individual differences and habituation

  1. Kuklane K, "Protection of feet in cold exposure" https://pubmed.ncbi.nlm.nih.gov/19531910/

  2. Castellani JW et al., "Effect of localized microclimate heating on peripheral skin temperatures and manual dexterity during cold exposure" https://pubmed.ncbi.nlm.nih.gov/30138077/

  3. Greenfield AM et al., "Influences of ovarian hormones on physiological responses to cold in women" https://pubmed.ncbi.nlm.nih.gov/35655670/

  4. Yurkevicius BR et al., "Human cold habituation: Physiology, timeline, and modifiers" https://pubmed.ncbi.nlm.nih.gov/36106151/

Prevention, recognition and practical planning

  1. Castellani JW et al., "American College of Sports Medicine position stand: prevention of cold injuries during exercise" https://pubmed.ncbi.nlm.nih.gov/17095937/

  2. Paal P et al., "Accidental Hypothermia: 2021 Update" https://pubmed.ncbi.nlm.nih.gov/35010760/

  3. NHS, "Hypothermia" https://www.nhs.uk/conditions/hypothermia/

  4. Met Office, "Wind chill factor" https://weather.metoffice.gov.uk/learn-about/weather/types-of-weather/wind/wind-chill-factor

  5. Mountain Rescue England and Wales, "Stay safe" https://www.mountain.rescue.org.uk/safety/

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