What to do after a cold plunge: rewarming, the afterdrop and when to call 911

Short answer: Get out slowly, dry off, change into dry layers with a hat, and stay with someone until you are steady. Your core temperature can keep falling after you leave the water, which is the afterdrop, but the studies that measured it used longer or colder exposures than a short plunge, and we found no study that timed it after a few minutes in a tub. Call 911 for confusion, slurred speech, stumbling, unusual drowsiness, chest pain, shivering you cannot control, or a faint you do not recover from within a couple of minutes. Hold off on the hot shower, the sauna and the drive home until you are steady.

This guide is general information, not medical advice. If you have a heart, lung or circulation condition, your own clinician’s advice comes first.

We did not visit or test any venue or tub. Everything here comes from the health bodies, makers and studies named, read between Oct. 24 and Nov. 2, 2026.

When to call 911 after a cold plunge

Being cold and shivering with a clear head is what the 2024 American Heart Association and American Red Cross first aid guidelines call simple cold stress. Keep warming up and keep someone with you. The signs below are different.

Sign	Who says so	What to do
Confusion, mumbling speech, unable to stay awake, stumbling, or unable to help take off wet clothes	The 2024 first aid guidelines, as potential signs of life-threatening hypothermia	Call 911 and keep warming the person
Shivering that cannot be controlled, or shivering that stops while the person is still cold	MedlinePlus, which says to call 911 anytime you suspect hypothermia	Call 911
Slurred speech, fumbling hands, memory loss or unusual tiredness	CDC’s warning signs of hypothermia; below 95° F, it says to get medical attention immediately	Call 911
Rigid muscles, blue skin or an erratic heartbeat	Plunge’s safety notice, which says to stop and call 911	Call 911
Crushing or squeezing pressure in the chest, pain spreading to the jaw or left arm, or chest pain with a racing heart or shortness of breath	MedlinePlus on chest pain	Call 911
A faint with no recovery within a couple of minutes, or with chest pain or a pounding or irregular heartbeat	MedlinePlus on fainting, which also says to call if the person is pregnant, over age 50 or has diabetes	Call 911
Hives with fainting, wheezing or shortness of breath	Cleveland Clinic on cold urticaria, which calls these reactions very rare; MedlinePlus says to call 911 for anaphylaxis	Call 911

CDC warns that low body temperature affects the brain, so a person may not know it is happening. That is why someone else needs to be watching.

While help is on the way, the NHS says to remove wet clothing, wrap the person in a blanket or dry towel with the head covered, give a warm non-alcoholic drink only if they are fully awake, and stay with them. It also says not to drive yourself: ask someone to drive you or call for an ambulance.

The first minutes after you get out

1. Get out slowly and hold on. Renu’s manual says to slowly exit, and Plunge says to use caution when entering and exiting.
2. Dry off and change. Cleveland Clinic says: “Dry off quickly and put on warm clothes.” CDC’s travel guidance says to stay dry by layering and quickly changing any moist clothing.
3. Cover your head and neck. The first aid guidelines say head exposure causes a disproportionate increase in core cooling rate.
4. Have a warm drink and some food. CDC says warm drinks can help increase body temperature. The first aid guidelines recommend high-calorie food or drink for anyone alert with cold stress or mild hypothermia, at a temperature that will not burn. The NHS suggests sugary food like chocolate.
5. Stay somewhere warm, with someone, until you are steady. The National Weather Service says to get into a warm, dry, protected environment as quickly as possible after cold water.

We found no published time for this, so do not trust a fixed number of minutes: go by whether your head is clear and your walk is steady.

If you plunge outdoors, what you wear matters. A 2024 lab study of 15 men found an insulating robe with a vapor barrier beat a towel or foil blanket on skin temperature and heart rate over 15 minutes in front of fans. The robe’s maker funded it.

What the afterdrop is

The afterdrop is a continued fall in core temperature after you leave the cold. The National Weather Service warns that even out of cold water, core temperature can continue to drop.

The usual explanation is cold blood from your arms and legs flowing back to your core. A 2022 review of accidental hypothermia calls this reperfusion the main cause and says heat moving between colder and warmer body regions may also play a role.

An earlier experiment argued for heat movement instead, and found no afterdrop when rewarming was delayed or when cooling had been slow and prolonged. So it is well documented, but not fully settled and not universal.

Size is what matters. In the three studies below that print the drop at rest, it was a fraction of a degree Celsius.

For someone already hypothermic it is more serious: the same review says afterdrop may cause cardiac arrest in hypothermic patients. That is why the 911 signs come first on this page.

How long the afterdrop lasts: what each study measured

You will see exact minutes quoted for the afterdrop. This table holds what researchers measured, shortest exposure first.

PubMed searches on Nov. 2, 2026 found no study that timed the afterdrop after a plunge of a few minutes at rest. The two nearest, in the first rows, reported no effect on core temperature.

Study	Who	Cold exposure	What happened after getting out
Kauppinen, 1989	9 active winter swimmers, men	Brief head-out ice water immersion, length not given in the abstract	Rested at room temperature; the immersions did not disturb the thermal balance of the body core
Zhang and colleagues, 2022	11 males exercising in 39°C heat	3 minutes, whole body, at 15°C	Core temperature not affected
Peterson and colleagues, 2026	28 military personnel	10 minutes at 1.3 °C, outdoors in -4.2 °C air	40 minutes of low or moderate exercise rewarmed them about the same; moderate exercise did not worsen the afterdrop
Read and colleagues, 2024	15 healthy men	30 minutes at 14°C	Afterdrop of 0.16 to 0.18°C at 5 minutes; deep body temperature 36.98 to 37.09°C at 15 minutes
Grigg and colleagues, 2025	15 healthy adults	30 minutes at 16 °C, to the sternum	After-drop seen for 15 minutes
Seo and colleagues, 2013	9 healthy young men	60 minutes at 13 °C, to the hips	Rectal temperature fell approximately 0.5 °C more in 15 minutes of recovery; selective attention impaired
Nuckton and colleagues, 2000	11 swimmers	New Year’s Day Alcatraz swim at 11.7 °C (53.0 °F), no wetsuits	Afterdrop in 10 of 11, measured for up to 45 minutes; 5 of 11 below 36.0 °C, one below 35.0 °C
Giesbrecht and colleagues, 1997	8 volunteers	8 °C water until core reached 35.9 °C	Dried and in sleeping bags, shivering freely: afterdrop of 0.4 °C lasting 20.9 minutes
Drigny and colleagues, 2023	14 swimmers	An average of 194 minutes at 12.5 to 13 °C, some in wetsuits	Continued cooling for 25 minutes on average, longer with higher body mass index and fat mass

No number here transfers to two minutes in a tub, in either direction. Longer and colder cools more: a pooled analysis of 157 subjects immersed after exercise found 0.02°C more core cooling for every minute and 0.03°C for every degree colder, and the largest gap against no immersion came at 60 minutes.

So the part you control is in the tub. Cleveland Clinic says a session should never go longer than five minutes, beginners should keep to a minute or two, and water should not go below 40 degrees Fahrenheit, with 50 to 59 F (10 to 15 C) as a beginner’s range.

Moving or sitting still while you rewarm

Moving is common advice. Renu’s manual suggests walking or gentle stretching, and the Wim Hof Method’s page describes a horse stance. The evidence is more mixed than that.

Against moving right away: in volunteers cooled in 8 degrees C water, the afterdrop was 58% greater during treadmill exercise than during shivering in one study and 1.1 degrees C against 0.35 degrees C in another. The 2022 review sums it up: walking increases heat production but increases afterdrop.

For moving: that review also lists promoting active movements among the measures usually sufficient for mild hypothermia. MedlinePlus says muscular exercise is thought to be safe in a very mildly hypothermic person. A British mountain rescue series of 108 alert people with mild hypothermia who walked off reported no adverse medical events.

Shivering does real work too: the first aid guidelines say it can raise heat production about 5 to 6 times the resting metabolic rate.

We found no study of this after a short plunge. A cautious order is dry, dressed and seated first, then easy movement once you are steady. If you are dizzy, sit or lie down instead.

Hot shower after a cold plunge: what the guidelines say

The warning is real, but it is narrower than a flat never. The 2024 first aid guidelines call a warm shower or warm bath potentially harmful for someone with hypothermia and reduced responsiveness, because of afterdrop, low blood pressure, falls and drowning. For simple cold stress, the same guidelines say people were generally able to rewarm safely in warm water.

First aid advice stays cautious. The NHS says not to use a hot bath and MedlinePlus says not to use hot water on someone with hypothermia.

NewYork-Presbyterian warns that numb skin can be injured if you apply heat too quickly. Cleveland Clinic tells people with low blood pressure on standing to skip very hot baths and showers.

We found no study of a shower after a short plunge. The cautious reading: wait until you are dry, clear-headed and steady, keep the water warm rather than scalding, and sit down or get out if you feel lightheaded.

Warm water and the afterdrop: what the small studies found

The guidelines’ reassurance about warm water rests on one person in a lab. Cooled in 10 degrees C water, then rewarmed in a bath, the subject had an afterdrop in the first 15 minutes along with an abrupt fall in arterial pressure. With no added heat there was no afterdrop.

A 1992 study points the other way. Seven volunteers cooled for 2 hours at 15 degrees C rewarmed fastest in a 42 degrees C bath, with an afterdrop of 0.18 degrees C against 0.14 degrees C in blankets, and the authors recommended the bath for mild hypothermia.

Adding external warming also shrank the afterdrop in 11 volunteers whose temperature control was blocked with medication, 0.3°C against 0.7°C.

All of these tested people deliberately cooled toward hypothermia, not a short plunge, so they tell you little about the size of the risk. They do show that the blood pressure effect can happen and that warm water is not automatically harmful.

Sauna after a cold plunge: the sources disagree

Cleveland Clinic says you may even want to try sauna therapy after a cold plunge. NewYork-Presbyterian’s sports medicine article says a safer approach might be to let the body return to normal temperature before moving from one to the other, and to avoid extremes if you alternate quickly.

The American Lung Association warns that switching between sauna heat and icy water can raise blood pressure or cause shock, and says to consult your provider first. A 2026 emergency medicine review says repeated cycles may impose substantial stress on the heart and circulation, and advises caution with rapid standing.

A sauna is not gentle heat: Cleveland Clinic says traditional saunas are typically heated between 150 and 195 degrees Fahrenheit.

The lab studies are mixed. In nine men in 1989, alternating heat and cold put the most intensive strain on the heart.

Sixteen healthy adults tolerated 85°C sauna rounds better with a 90-second dip at 20°C in the cooling break, and 37 men, some with heart failure or coronary artery disease, tolerated an 80°C sauna followed by immersion at 12°C, though systolic pressure fell in the sauna. None tested a very cold plunge followed straight away by a hot room in the general public.

If you do it, wait until you are dry and steady and leave at the first dizziness. Our guides to contrast therapy and the right order cover sequencing.

Fainting and standing up after a plunge

Two things can drop your blood pressure as you get out. One is standing: Cleveland Clinic says dizziness or lightheadedness when you stand is the main symptom of orthostatic hypotension, and some people faint.

The other is leaving the water. A 2026 review says collapse around rescue is driven primarily by the abrupt loss of water pressure on the body. The National Center for Cold Water Safety, a safety group focused on paddlers rather than a health agency, says this collapse is not well understood and that people who have been in cold water for a long time can lose consciousness when removed.

Those accounts come from long immersions and rescues. We found no study of fainting after a short plunge.

So stand up slowly, using the rail or a hand. If you feel faint, the NHS says to lie down with your legs raised, or sit with your head lowered between your knees.

Anyone who has fainted should get checked: the NHS says to see a GP, and MedlinePlus says to see your provider if you have never fainted before. Our guide on feeling faint in a sauna covers the first aid.

Can you drive after a cold plunge?

We found no official rule and no study on driving after a plunge. What exists points to waiting.

The NHS says that if you think you have hypothermia, you should not drive yourself to the hospital. CDC says body temperature that is too low leaves a person unable to think clearly or move well.

Three sources point the same way, though none is specific to a short plunge. In the 2013 study in the table, nine men immersed to the hips for 60 minutes in 13 °C water had impaired selective attention during the afterdrop.

A 2021 systematic review found cold exposure impaired cognitive performance in 15 of 18 settings, even before hypothermia. And 29 service members immersed for 10 minutes at 1.3 °C had impaired standing balance after changing into dry clothes, still below baseline after 40 minutes of active rewarming.

The cautious reading: do not drive while you are shivering, dizzy or fumbling. If your plunge is far from home, plan to wait it out or bring a driver.

Do not plunge or rewarm alone

Exercise scientist Lee Hill, quoted by American Heart Association News, says: “Never, ever do a cold water swim on your own”.

The makers print the same rule for tubs. Renu says not to leave the tank unattended while in use. Plunge says to use it under supervision until you know how your body reacts.

Ice Barrel recommends always having a partner present. NewYork-Presbyterian says to have someone with you who can assist if necessary. The American Lung Association says that if cold shock leads to fainting while unsupervised, the person is at risk of drowning.

Someone should stay after you get out too, because the signs at the top of this page are hard to spot in yourself.

At a studio, tell staff when you go in. At home, have the other person stay until you are dressed and steady. Our guide to home setups covers the rest of the makers’ rules.

Breath-hold exercises do not belong near the water at any point. The Wim Hof Method says not to do its breathing in the water, and CDC has documented drownings from breath-holding underwater.

Who should check with a clinician before plunging

Cleveland Clinic names heart disease, high blood pressure, diabetes, pregnancy, peripheral neuropathy, poor circulation, venous stasis and cold agglutinin disease. Others add to that list:

• Heart rhythm and circulation. Harvard Health says anyone with a heart rhythm disorder such as atrial fibrillation should avoid cold plunges, and the same for peripheral artery disease or Raynaud’s.
• Any cardiac history. A preventive cardiologist quoted by American Heart Association News says he would caution against it, and that beta blockers could make it harder for the body to adapt.
• Lung disease. The American Lung Association names chronic lung disease and pregnancy, and says to consult your provider first.
• Medications. Plunge says to consult a physician if you take medication that may induce drowsiness or affect heart rate, blood pressure or circulation. Cleveland Clinic says sedatives, opioids, phenothiazine antipsychotics and clonidine can impair your response to cold. Our medication and heat checklist and guide to common medications cover this.
• Nerve conditions. NewYork-Presbyterian names multiple sclerosis and peripheral neuropathy.
• Cold urticaria. Cleveland Clinic says to avoid cold baths and showers.

Stay out if you are sick: Renu says not to use the tank if you are vomiting, have diarrhea or have an infectious disease. Our pregnancy guide and blood pressure guide cover those cases.

Children and teens after a cold plunge

The American Academy of Pediatrics says hypothermia can occur more quickly in children than in adults, and to call 911 at once if you suspect it. The National Center for Cold Water Safety says children cool much faster because of their smaller body size.

The makers draw a line at 18. Renu says its tank is not designed for children under 18. Plunge says use by anyone under 18 must be approved by a medical professional and supervised at all times.

Ice Barrel says it is not recommended for children.

The few studies measure the first seconds, not the rewarming. Healthy children in 11 °C water had heart rate up 31% and breathing up 58%, a lower response than in adults. Twenty adolescents in 2°C water showed a low risk of severe arrhythmias on brief immersion, and the authors warn the risk could rise with face submersion and breath-holding.

We found no study of the afterdrop or rewarming in children. Our guide to sauna and cold plunge for kids and teens covers the rest.

Alcohol and cold plunges

Alcohol does not warm you up. The American Red Cross says it may temporarily make a person feel warmer but actually increases loss of body heat. The NHS, CDC and MedlinePlus all say not to give it to someone with hypothermia, and CDC lists people who drink alcohol among those at risk.

The makers ban it. Plunge says never to use alcohol or drugs before or during use, because they can greatly increase the risk of fatal hypothermia, unconsciousness or drowning. Renu says not to drink before or during use, because alcohol can impair judgment and increase the risk of accidents.

The lab evidence adds a nuance. In a 1979 study of 10 people immersed at 10 degrees C, moderate alcohol did not change cooling or the afterdrop, and the authors blamed accidents for the link between alcohol and water deaths. So at moderate doses the risk they point to is accidents, not faster cooling.

Our guide on alcohol and saunas covers the heat side.

What does not help while you rewarm

Some habits feel useful and are not, at least for someone who is truly cold. These rules come from first aid for hypothermia, so they are the cautious version for a short plunge.

• Rubbing your arms and legs. The NHS says not to, and the first aid guidelines say heat sources, rubbing and massage should not be applied to the limbs of a person with hypothermia.
• Small hand or boot warmers on their own. The guidelines say they are not effective as the main way to rewarm.
• A hot water bottle or heating pad on bare, numb skin. The Red Cross says to wrap them in thin, dry cloth to protect the skin, and NewYork-Presbyterian warns about heat on numb skin.
• Very hot drinks. The guidelines say drinks should be at a safe temperature to avoid burning the esophagus.
• Coffee as your warm drink. The Red Cross advises against caffeinated drinks for someone with hypothermia.

Warm the trunk first: the National Weather Service says to warm the core, not the hands and feet, and to warm the person slowly.

Does any routine after a plunge speed recovery?

We found no trial that compared rewarming routines after a plunge on soreness or any other benefit, and none that tested whether a hot shower afterward cancels a benefit.

Routines are still sold as recovery. Renu’s manual has a post-immersion recovery list: light activity, drinks to replace fluids, and rest to reap the therapeutic benefits. It names no study.

What has been tested is the immersion itself. A Cochrane review of 17 small trials and 366 participants found some evidence that cold water immersion reduces muscle soreness after exercise, with low study quality. A 2023 meta-analysis of 28 studies also favored it for soreness.

Harvard Health adds that it is not clear the practice enhances performance, and Cleveland Clinic warns against plunging within four hours of a muscle-building workout. Our guide on plunging after a workout covers that.

So warm up for safety and comfort. We found nothing that shows the order of your towel, shower and snack changes the result.

Cold plunge aftercare at a glance

Step	What the sources say	What to do
Getting out	Use caution (Plunge); slowly exit (Renu)	Hold on, stand up slowly
Wet swimwear	Remove wet clothing (NHS, CDC)	Dry off and change first
Head and neck	Head exposure speeds core cooling (2024 first aid guidelines)	Hat and a dry layer
Warm drink and food	Warm drinks can help (CDC); high-calorie if alert (2024 guidelines)	Once you are fully awake; no alcohol
Shivering, clear head	Simple cold stress (2024 guidelines)	Keep warming, someone watches
Shivering you cannot control, confusion, slurred speech	Signs of hypothermia (MedlinePlus, CDC, 2024 guidelines)	Call 911
Gentle movement	Mixed: makes heat, but enlarged the afterdrop in the lab	Only once you are steady
Warm shower	Generally safe with simple cold stress; potentially harmful with reduced responsiveness (2024 guidelines)	Only when clear-headed and steady
Sauna	Sources disagree (Cleveland Clinic, NewYork-Presbyterian, American Lung Association)	Wait until steady; leave at the first dizziness
Feeling faint	Lie down with legs raised (NHS)	Stop, lie down, get checked
Driving	No rule found; do not drive yourself with suspected hypothermia (NHS)	Wait until steady
Being alone	Never, ever on your own (AHA News quote); partner present (Ice Barrel)	Keep someone with you

FAQ: rewarming after a cold plunge

How long does the afterdrop last?

We found no study that timed it after a short plunge. In longer exposures, studies recorded 15 minutes after 30 minutes at 16 °C, and 25 minutes on average after swims averaging 194 minutes. Go by how clear your head is and how steady you are, not a number.

Is shivering after a cold plunge normal?

Shivering is how the body makes heat, and the 2024 first aid guidelines treat cold and shivering with a normal mental state as simple cold stress. The National Center for Cold Water Safety calls it an early warning sign that you are losing too much heat, so keep warming up. Call 911 if you cannot control it, or if you have confusion, slurred speech or stumbling.

Should I take a hot shower after a cold plunge?

Wait until you are dry, clear-headed and steady, then keep it warm rather than scalding. The 2024 first aid guidelines call warm showers potentially harmful for someone with reduced responsiveness because of low blood pressure, falls and drowning. We found no study of a shower after a short plunge.

Can I go straight into a sauna after a cold plunge?

The sources disagree. Cleveland Clinic suggests a sauna as one way to warm up, while NewYork-Presbyterian says a safer approach might be to let your body return to normal temperature first. Ask your clinician if you have a heart, lung or blood pressure condition.

When can I drive after a cold plunge?

We found no official rule. Wait until you have stopped shivering and feel steady and clear-headed. If you think you have hypothermia, do not drive yourself: the NHS says to ask someone to drive you or call for an ambulance.

Should I keep moving or sit down after a plunge?

Sit first while you dry off and change. Lab studies found exercise enlarged the afterdrop compared with shivering, though other sources accept gentle movement in someone only mildly cold. If you feel dizzy, sit or lie down.

Does a hot shower cancel the benefits of a plunge?

We found no trial that tested this. Claims that you must warm up naturally to keep a benefit have no study behind them that we could find.

The bottom line on rewarming after a plunge

Your core temperature can keep falling after you get out, but we found no reliable number of minutes for a short plunge, so treat any printed figure with care. Dry off, change, cover your head, have a warm non-alcoholic drink, and stay with someone until you are steady.

Hold off on the hot shower, the sauna and the drive until then. Call 911 for confusion, slurred speech, stumbling, shivering you cannot control, chest pain or a faint you do not recover from quickly.

Time and temperature in the tub set how cold you get, so keep the plunge short. If you have a heart, lung or circulation condition, ask your clinician before you start.

To find a cold plunge or sauna studio near you, start with our city wellness maps.

Related reading on cold plunge safety

• Is cold plunging safe? Who should avoid it
• Ice baths & cold plunges: what they do, and how to start without hurting yourself
• Polar plunge safety
• What to do if you feel faint in a sauna
• Sauna or cold plunge first: the right order