Whether you’re responding to an emergency on a mountainside, a roadside or even a sports field, hypothermia remains one of the most dangerous, and often underestimated, threats. In trauma cases, accidental hypothermia has been shown to increase the risk of mortality by more than 3X compared to normothermic patients (Chughtai et al., 2011). Recognising the early signs and responding appropriately can be the difference between life and death.
Why Is Hypothermia Such a Challenge?
Maintaining a stable core temperature is essential for organs to function properly. In normal conditions, our bodies regulate temperature with relative ease, but in cold environments or when the body is experiencing shock or injury, heat loss quickens.
When the body loses more heat than it can produce, hypothermia sets in. Even mild hypothermia (core temp below 35°C) can impair judgement and motor control. As it worsens, the body’s ability to generate heat shuts down, potentially leading to unconsciousness if untreated or, in extreme cases, death.
Factors that exacerbate hypothermia:
- Convection: Wind strips away the warm layer of air surrounding the body, significantly increasing the rate of cooling, even at relatively mild temperatures.
- Conduction: When in direct contact with cold surfaces (like the ground or wet clothing), heat is transferred away from the body.
- Evaporation: Moisture on the skin, from sweat, wet clothing or rain, cools the body as it evaporates.
Recognising the Stages of Hypothermia
Early recognition is key to responding to hypothermia effectively. Whilst stages of hypothermia are often categorised by body temperature (mild hypothermia = 32 – 35°C, moderate hypothermia = 28 – 32 °C, and severe hypothermia = below 28°C), due to the challenges associated with taking an accurate reading of a person’s temperature, using tympanic, axillary and forehead thermometers in cold settings, the experts at World Extreme Medicine recommend looking out for visible signs of hypothermia:
The five “Umbles”:
- Grumbles – change in behaviour, negative attitude and complaints
- Fumbles – reduced fine motor skills, difficulty operating buttons/zips due to cold peripheries
- Mumbles – quiet, slowed or slurred speech
- Stumbles – off balance, falling behind, tripping over
- Crumbles – disorientation, patient combative, reduced conscious level or in rare cases paradoxical undressing (implies moderate to severe hypothermia)
Best Practice: How to Prevent and Treat Hypothermia
There is no single solution for treating hypothermia; effective intervention depends on both the stage of hypothermia and the specific circumstances of the incident.
Mild Hypothermia:
Mild hypothermia may be managed through shelter, sugary food, warm fluids, and controlled movement, provided the patient is alert and able to participate in rewarming. Though previously advised against, a 2024 case series by Mountain Rescue teams in Great Britain (Wilderness & Environmental Medicine) tracked 108 patients with clinically diagnosed mild hypothermia, all alert on the AVPU scale, who were successfully evacuated by walking. In 39% of cases, rescuers walked stationary patients off the mountain without delay. All patients survived, with no adverse events reported, proving that this can be an effective method for managing patients with mild hypothermia, where there is access to a warm shelter or vehicle.
Moderate to Severe Hypothermia:
However, in cases where the casualty is unable to walk, is injured or cannot be evacuated to a warmer environment rapidly, best practice guidelines recommend establishing a sheltered environment where possible and employing the burrito wrap technique — a layered insulation and vapour barrier system that mimics an enclosed microclimate (Wilderness Medical Society, 2019; WEM, 2024). This approach helps reduce further conduction, convection, and evaporative heat loss while supporting the body’s own thermogenic mechanisms (Forgey et al., 2019; Mountain Rescue England & Wales, 2022).
The ‘Burrito Wrap’
A standard burrito wrap is a passive rewarming technique that includes:
- Inner vapour barrier: Foil, plastic wrap or *emergency blanket placed directly against dry clothing or skin
- Insulation: Dry insulating layers such as a sleeping bag or blankets
- Ground insulation: Sleeping pad, foam mat, rucksack to insulate from the ground
- Outer vapour barrier: A tarp, survival bag, or outer bivvy sack
- Face remains exposed for airway management and monitoring
When to Add Active Heating
In moderate hypothermia (core temp 32–28°C, reduced consciousness, reduced shivering), passive rewarming may not be enough. In this case, active external heat can be added to the trunk, but with strict precautions:
- Apply heat packs only to the chest, armpits, or upper back
- Never apply heat to the limbs – doing so can cause afterdrop or cardiovascular collapse
- Never place heat sources directly on skin, but buffer with insulation to prevent burns
- Monitor closely (pulse, mental status, temperature)
For further guidance on recognising and treating the stages of hypothermia, we recommend reading the WEM Cold Medicine Guide
How THERMARMOUR Passive Warming Can Help
THERMARMOUR’s passive warming *emergency blankets and ponchos were developed in collaboration with first responders to insulate patients in prehospital and perioperative environments.
Unlike conventional blankets, THERMARMOUR blankets and ponchos:
- provides effective insulation, significantly outperforming foil blankets through the addition of reinforced laminate and fleece layers which reflect and capture heat.
- acts as a vapour barrier, making it ideal for use in the burrito wrap method, reducing evaporative heat los
- Is water and tear resistant – optimised for strength and durability in the elements.
- is lightweight, compact and easy to deploy in situations where there are space and weight constraints.
In addition, THERMARMOUR Hypothermia Evacuation Bags:
- are designed to fully cocoon the patient during evacuations, if sheltering in place is not an option.
- include carry handles and drag point to evacuate the patient as a team or individual.
- include 4 easy access panels to review injuries and monitor the patient.
From mountain rescue teams to frontline medics in emergency services and militaries, THERMARMOUR is trusted by professionals in the emergency field.
To Shop or Learn more, visit https://thermarmour.com/
You may also be interested in:
Preventing Hypothermia from the Ward through to the Recovery room
Preventing heat loss during patient transport and handover to improve patient outcomes
THERMARMOUR’s Guide to Staying Warm This Winter
References:
- Chughtai, T., et al. (2011). Hypothermia is an independent predictor of mortality in trauma patients. The Journal of Trauma, 71(2), 387–393. DOI: 1097/TA.0b013e3182127c21
- Forgey, W.W., et al. (2019). Wilderness Medical Society Clinical Practice Guidelines for the Out-of-Hospital Evaluation and Treatment of Accidental Hypothermia. Wilderness & Environmental Medicine, 30(4), 401–417. DOI: 10.1016/j.wem.2019.02.005
- World Extreme Medicine (2024). Expedition & Polar Medicine Course Materials.
- Mountain Rescue England & Wales (MREW) (2022). Hypothermia and Cold Casualty Guidelines.
- Advanced Wilderness Life Support (AWLS) (2023). Clinical Field Protocols: Hypothermia Management.
Categories: Emergency, Medical, Uncategorized
Tags: best practices, emergency, emergency blanket, emergency poncho, emergency products, first aid, hypothermia in rescue, medical kit, mountain rescue, patient warming, rescue, water rescue
