The fastest way to warm someone up is to get them out of the cold, replace any wet clothing with dry layers, and focus heat on the center of their body: chest, neck, armpits, and back. How aggressively you rewarm depends on how cold they are. A person who’s chilly after being outside too long needs different care than someone showing signs of hypothermia, where core body temperature drops below 95°F (35°C).
Assess How Cold They Are
Normal body temperature sits around 98.6°F. Once core temperature falls below 95°F, hypothermia begins, and the rewarming approach changes at each stage.
In mild hypothermia (95°F to 89.6°F), the person will shiver, move clumsily, and seem confused or unusually sleepy. They may have a weak pulse and pale skin. Shivering is actually a good sign here: it means the body is still generating its own heat.
In moderate hypothermia (89.6°F to 82.4°F), shivering decreases or stops. Speech becomes slurred, skin turns bluish, muscles stiffen, and the person may lose consciousness. Heart rhythm can become irregular.
Severe hypothermia (below 82.4°F) is a medical emergency. The person stops shivering entirely, may have no detectable pulse, and can appear dead. Call emergency services immediately.
Get Them Sheltered and Dry
Move the person indoors if possible. If you’re stuck outside, shield them from wind, especially around the head and neck, where heat escapes quickly. Insulate them from the ground: lay down a blanket, sleeping pad, backpack, or even a pile of dry leaves before setting them on it. Cold ground pulls heat from the body through direct contact faster than most people realize.
Gently remove any wet clothing and replace it with dry layers, coats, or blankets. “Gently” matters here. Rough handling of a hypothermic person can trigger dangerous heart rhythms. Move them slowly and avoid jostling their limbs.
Focus Heat on the Chest and Core
This is the single most important principle of rewarming: warm the center of the body first. Apply heat to the chest, armpits, neck, groin, and back. Warm compresses, hot water bottles wrapped in a towel, electric blankets, or large heat packs all work. If you’re using a chemical hand warmer, wrap it in fabric so it doesn’t burn the skin.
Large heat packs that cover more surface area are significantly more effective than small chemical packs for raising core temperature. Small packs don’t produce enough heat to make a real difference at the core, though they can help with comfort on hands and feet once the torso is being warmed.
Wrapping heat sources inside insulation (blankets, sleeping bags) with a vapor barrier like a plastic tarp or space blanket on the outside traps the most warmth. The vapor barrier prevents heat from escaping through evaporation, which is one of the biggest sources of heat loss.
Why You Should Not Warm the Arms and Legs First
This is counterintuitive but critical. When someone is hypothermic, their blood vessels in the arms and legs constrict to keep warm blood circulating around vital organs. If you warm the extremities first, those vessels open up suddenly. Cold blood from the limbs rushes back to the heart, which can cause core temperature to drop even further. This is called “afterdrop.”
Worse, the sudden shift in blood flow can cause a dangerous drop in blood pressure or even cardiac arrest, sometimes called rewarming collapse. Heating or massaging the limbs of a moderately to severely hypothermic person puts unnecessary strain on an already stressed heart. Let the core warm first, and the extremities will follow.
Give Warm Drinks if They’re Alert
If the person is conscious and able to swallow, warm (not hot) liquids help from the inside. Sweet, non-caffeinated drinks like warm water with sugar, herbal tea, or broth are good choices. The sugar provides quick calories the body can convert to heat.
Avoid alcohol entirely. It feels warming because it dilates blood vessels near the skin, but that actually accelerates heat loss from the core. Caffeine is also best avoided because it can contribute to dehydration and may stress the cardiovascular system during rewarming.
Use Body Heat When Nothing Else Is Available
If you have no heat packs, blankets, or shelter, body-to-body contact is a legitimate rewarming method. Remove outer layers and press your chest and torso against the person’s chest and torso, then cover both of you with whatever insulation you have. The goal is skin-to-skin contact along the trunk, not the limbs.
Research on skin-to-skin warming in clinical settings confirms that direct body contact effectively transfers heat, particularly when the contact is chest-to-chest and sustained. In studies on newborns, skin-to-skin care was at least as effective as incubator warming for raising body temperature, and longer duration of contact correlated with greater temperature increases. The same physics applies to adults: your body is a roughly 98.6°F heat source, and direct contact transfers that energy efficiently.
What Works for Everyday Cold Exposure
Not every situation involves true hypothermia. If someone comes inside shivering after shoveling snow or waiting at a bus stop, the approach is simpler but follows the same logic.
- Dry layers first. Swap out anything damp from sweat or snow. Cotton holds moisture and keeps pulling heat away, so wool or synthetic fabrics are better base layers.
- Warm the core. A warm drink, a heating pad on the chest or back, or simply wrapping up in a blanket on the couch all help. The person’s own shivering will do most of the work at this stage.
- Cover the head. A significant amount of heat escapes from an uncovered head, and a hat or hood makes a noticeable difference.
- Warm the room. If you’re indoors, raise the thermostat or sit near a heat source. A warm bath is fine for someone who’s just cold (not hypothermic), but keep the water comfortably warm rather than hot to avoid a sudden blood pressure shift.
When Rewarming Becomes a Medical Emergency
Mild hypothermia can usually be managed with the steps above. But if shivering has stopped, the person is confused or unconscious, their skin looks blue, or their pulse is weak or irregular, they need emergency medical care. These are signs of moderate to severe hypothermia, where the heart is vulnerable to dangerous rhythm changes.
While waiting for help, keep the person horizontal, insulated, and still. Do not try to rewarm them aggressively. Gentle passive warming (blankets, vapor barriers, heat on the torso) is safer than rapid external heating when body temperature has dropped significantly. Handle them as carefully as you would someone with a spinal injury. If they have no pulse and aren’t breathing, begin CPR, but know that a severely hypothermic person can sometimes appear lifeless and still recover with hospital rewarming.