Hypothermia symptoms can start with shivering, clumsy hands, exhaustion, and confusion, then worsen to slurred speech, weak pulse, shallow breathing, and unconsciousness. Yes, it is a medical emergency when core body temperature drops below 95°F [35°C] or a hiker is cold, wet, and mentally altered.
What are hypothermia symptoms on the trail?
Early hypothermia often looks like a cold hiker who is suddenly moving poorly and thinking poorly.
The trail version is rarely dramatic at first. Someone gets soaked in rain, sweats through a climb, sits too long in wind, falls into cold water, or bonks hard near dusk. Then the small clues stack up. The CDC lists shivering, exhaustion, confusion, fumbling hands, memory loss, slurred speech, and drowsiness as warning signs.
- Hard shivering or shivering that later stops
- Fumbling with zippers, buckles, trekking poles, or a stove
- Stumbling on easy ground
- Slow answers, blank staring, poor decisions
- Slurred speech or mumbling
- Sleepiness, apathy, or “I’m fine” when they clearly are not
- Cold, pale skin
- Slow, shallow breathing in more serious cases
The brain gets cold, too. That is why a hypothermic hiker may refuse a jacket, sit down in a bad spot, or insist the group should keep moving in the wrong direction. Do not wait for the person to make good choices. Cold brains make bad calls.
What are the signs of hypothermia by stage?
The signs of hypothermia usually move from shivering and clumsiness to confusion, drowsiness, and collapse.
| Trail severity | What you may see | What it means for your group |
|---|---|---|
| Mild | Shivering, cold hands, stumbling, slow tasks, cranky mood | Stop heat loss now; add dry insulation, food, warm drinks if safe to swallow |
| Moderate | Confusion, slurred speech, poor coordination, intense fatigue, shivering may weaken | Treat as urgent; shelter, rewarm the core, and plan evacuation |
| Severe | Very drowsy or unconscious, weak pulse, slow breathing, no obvious shivering | Call 911 or activate rescue; handle gently and keep warming while help comes |
A thermometer can help, but do not let gear decide for you. If the person is cold, wet, and mentally off, act. The Mayo Clinic defines hypothermia as body temperature below 95°F [35°C] and recommends emergency help when you suspect it.
What should you do first for hypothermia on the trail?
Stop heat loss first, then rewarm the person slowly and safely.
- Get out of wind, rain, and cold ground contact. Move to a tent, tarp, dense trees, a cabin, a vehicle, or the lee side of a boulder. Put a sleeping pad, pack, rope, or spare clothing under the person.
- Remove wet layers if you can do it without rough handling. Cut clothing off if needed. Replace it with dry base layers, fleece, puffy insulation, rain gear, a hat, and dry socks or mittens.
- Wrap the hiker like a burrito. Use a sleeping bag, quilt, emergency bivy, tarp, pack liner, or space blanket. Trap heat around the head and neck, but keep the face clear for breathing.
- Warm the core. Put warm water bottles or wrapped heat packs near the chest, armpits, neck, and groin. Do not put hot items directly on skin.
- Give warm, sweet drinks only if the person is fully awake and can swallow. Think cocoa, tea, warm electrolyte drink, or soup. No alcohol.
- Call for help early if the person is confused, getting worse, or cannot keep moving safely. Use 911, satellite SOS, ranger dispatch, or another reliable emergency channel.
- Monitor breathing and responsiveness. If the person shows no signs of life, follow your CPR training and emergency dispatcher instructions.
The NIH MedlinePlus first aid guidance also says to remove wet clothing, warm the neck, chest wall, and groin, stay with the person, and call emergency services if confusion or thinking problems appear.
What should you not do if someone has hypothermia?
Do not rewarm a hypothermic hiker with rough handling, alcohol, direct heat, or a hot bath.
Cold-stressed hearts can be irritable. Treat the person like fragile gear. Move them only as much as needed to get them protected, dry, insulated, and ready for evacuation.
- Do not rub or massage arms and legs. That can damage cold tissue and may worsen circulation problems.
- Do not put them in a hot shower, hot bath, or near a blasting fire. Fast external heating can burn numb skin and may pull cold blood toward the core.
- Do not give alcohol. It can worsen heat loss and judgment.
- Do not give food or drink to a drowsy, confused, or unconscious person. Choking risk is real.
- Do not assume a motionless cold person is dead. Activate rescue and follow emergency instructions.
The Wilderness Medical Society’s accidental hypothermia guideline supports gentle handling, field assessment based on alertness and shivering, and evacuation decisions tied to severity.
When to see a doctor
Call 911 right away if a cold hiker is confused, very drowsy, unconscious, or has slow breathing.
On trail, “see a doctor” often means “start evacuation now.” Hypothermia is not something to sleep off in a damp tent. Medical care is needed when symptoms are more than mild shivering, when the person does not improve after dry insulation and shelter, or when cold exposure came with injury, immersion, exhaustion, diabetes, heart disease, or possible frostbite.
Get medical help if any of these are present:
- Confusion, memory loss, slurred speech, or odd behavior
- Shivering that stops while the person is still cold
- Weak pulse, slow breathing, collapse, or unconsciousness
- Cold-water immersion
- Frostbite signs, such as numb, waxy, hard, pale, gray, or blistering skin
- No clear improvement after shelter, dry clothing, and core warming
Do not try to diagnose severity in the backcountry. Your job is simpler: protect from further cooling, rewarm safely, keep watch, and get help.
How can you prevent hypothermia before it starts?
Stay dry, fed, sheltered, and ahead of wind chill.
Hypothermia is not reserved for deep winter. It can hit during cold rain, shoulder-season wind, river crossings, wet snow, long breaks, and sweaty climbs followed by exposed ridgelines. The danger rises when moisture and wind gang up on fatigue.
- Pack a waterproof shell and use it before your insulation gets soaked.
- Carry a dry warm layer in a pack liner or dry bag.
- Change out of sweaty layers before a long stop.
- Eat steady calories and drink enough to keep moving well.
- Keep hat, gloves, and spare socks easy to reach.
- Turn around before the slowest hiker is drained.
- Carry a way to call for help where cell service is weak.
- Know your group’s cold-risk members: kids, older adults, very lean hikers, exhausted hikers, and anyone with medical conditions affecting temperature regulation.
A tiny shelter kit can buy time: emergency bivy, foam sit pad, lighter, fire starter where fires are allowed, extra puffy, and a hot drink plan. The best first aid is never needing the rescue.
Related reading
- Lyme Disease Symptoms After a Hike
- Heat Stroke Symptoms on the Trail
- Hantavirus and Camping: Cabins, Shelters and Risk
- Electrolytes for Hikers: What They Are and How Much You Need
FAQ
Can you get hypothermia above freezing?
Yes. You can become hypothermic in cool weather if rain, sweat, wind, or cold water strips heat faster than your body can replace it. A wet hiker sitting in wind at 45°F [7°C] can be in real trouble.
What is the first sign of hypothermia?
Shivering is often the first obvious sign. On trail, also watch for clumsy fingers, slow movement, poor balance, and a sudden drop in mood or decision-making.
Does shivering stopping mean the person is better?
No. Shivering can stop when hypothermia becomes more severe and the body is running out of heat-producing power. If a cold person stops shivering and seems sleepy or confused, treat it as an emergency.
Should you let a hypothermic hiker sleep?
No, not if they are cold and mentally altered. Sleepiness can be a worsening symptom, so keep the person sheltered, insulated, monitored, and on the path to medical care.
What is the best trail first aid item for hypothermia?
Dry insulation plus windproof shelter is the core of treatment. A sleeping bag, emergency bivy, tarp, foam pad, dry puffy, and warm water bottle work together better than one shiny space blanket alone.
When should you call 911 for hypothermia?
Call 911 when the person is confused, drowsy, unconscious, breathing slowly, unable to walk safely, or not improving after warming steps. If you suspect hypothermia and evacuation is difficult, call early rather than waiting for symptoms to get worse.