Hypothermia happens when your body temperature drops way below normal, causing the circulatory, respiratory, and nervous systems to slow down. Normal body temperature is around 98.6°F (37°C). Hypothermia happens if your temperature drops to 96°F (35.5°C) or below.
Hypothermia often happens gradually, but it can happen within minutes, such as if someone falls through the ice into cold water. Then your body starts to lose heat faster than it can produce it. Severe hypothermia can cause an irregular heartbeat, which can lead to heart failure and death. More than 700 deaths in the United States each year are caused by hypothermia and frostbite.
Signs and Symptoms
Signs and symptoms of hypothermia may include:
- Skin that is cold to the touch
- Shivering at first, then not shivering
- Lethargy, drowsiness
- Weakness, clumsiness
- Irritability, combativeness
- Confusion, delirium, hallucinations
- Slow reflexes
- Seizure, stupor, or coma
- Slowed, shallow, or arrested breathing
- Slowed, irregular, or arrested heartbeat
What Causes It?
Hypothermia can happen from:
- Accidental exposure to cold
- Immersion in cold water
- Injury from a serious accident
Wearing wet clothes can raise your risk for hypothermia. Older people are especially at risk.
Hypothermia may develop over hours or days if your body cannot regulate heat as it should, if you cannot sense how cold it is, or if you live in a cold environment in the winter. Some conditions can also cause your body to have trouble producing heat.
Who is Most At Risk?
Risk factors include:
- Exposure to cold.
- Immersion in cold water.
- Severe injury, especially brain injury or burns.
- Not moving for long periods of time.
- Age-related physical problems. More than half of all hypothermia-related deaths happen in people over age 65.
- Conditions such as heart failure, lung infection, other infections, or endocrine problems.
- Drugs such as alcohol, tranquilizers, sedatives, hypnotics, or antipsychotics.
- Poverty, malnutrition, or homelessness.
- Mental impairment that causes someone to be unaware of cold.
What to Expect at Your Provider's Office
Severe hypothermia is a life-threatening condition. If you or someone you care for has symptoms of hypothermia, give first aid to warm them up and call 911 immediately.
You can usually prevent hypothermia by:
- Dressing warmly
- Being careful to stay warm and dry
- Recognizing the early symptoms
If you plan to be outdoors in cold weather, wear layers of insulated or moisture-wicking clothing, including a hat. Keep emergency supplies in your car when traveling. Avoid overexertion, eat enough food, drink enough fluids, and do not drink alcohol.
Social service agencies can help people who are prone to hypothermia, such as the elderly or the homeless, find housing, heat, and clothing. If you have elderly family members or neighbors, check on them when it is cold.
For mild hypothermia, warming up may be enough. Get out of the cold and remove wet clothing and replace it with dry, warm clothing and blankets. Give the person something warm to drink, but DO NOT give alcohol. Other techniques include using hot water bottles filled with warm water, warm (not hot) baths, or heat packs placed under the arms and on the chest, neck, and groin.
- Warm the arms and legs directly, for fear of forcing cold blood back toward the heart.
- Apply heating pads or electric blankets, because they can burn skin.
- Rub arms and legs.
Sharing body heat (lying with your skin touching the person's skin) may help. The person can also get into the heat escape lessening position (HELP), sitting with knees bent upwards so they are against the chest. This helps keep the body's trunk warm.
Watch the person's breathing. If they stop breathing and have no pulse, give CPR if you are trained to do so. Be careful, however, because a person with hypothermia may have a very slow heart rate that is hard to detect. You may need to check for a pulse for as long as 45 seconds or a minute.
At the hospital, the medical team will use heated IV (intravenous) fluids. The person may be wrapped with blankets in a warm room or put into a large tub of warm water. Warm humidified air may also be used.
Severe or complicated cases of hypothermia may need IV drug therapy.
Complementary and Alternative Therapies
The most important thing you can do for someone who has hypothermia is get them to a warm, safe place. There are no herbs or supplements that specifically treat hypothermia, but eating a healthy diet, including warm foods and soups may help lower your risk for hypothermia. Animal studies suggest that some herbs may affect body temperature and may help prevent hypothermia if used before, or just after, exposure to cold.
Always tell your health care provider about the herbs and supplements you are using.Nutrition and Supplements
These nutritional tips may help you stay healthy in cold climates:
- Eat warming spices in your foods, such as basil, ginger, turmeric, garlic, and cayenne.
- Eat antioxidant foods, including fruits (blueberries, cherries, and tomatoes), and vegetables (squash and bell peppers).
- Eat more hot soups made with fresh vegetables.
- Avoid caffeine and other stimulants, alcohol, and especially tobacco. Smoking causes blood vessels to narrow and may increase risk of hypothermia.
- Drink 6 to 8 glasses of water daily. Hydration is important in reducing problems from cold exposure.
- Exercise at least 30 minutes daily, 5 days a week.
Keeping your body healthy may help ward off hypothermia. Some people may benefit from taking a multivitamin daily, containing the antioxidant vitamins A, C, E, the B-vitamins and trace minerals, such as magnesium, calcium, folic acid, zinc, and selenium.Herbs
The use of herbs is a time-honored approach to strengthening the body and treating disease. Herbs, however, can trigger side effects and can interact with other herbs, supplements, or medications. For these reasons, you should take herbs only under the supervision of a provider.
You may use herbs as dried extracts (capsules, powders, or teas), glycerites (glycerine extracts), or tinctures (alcohol extracts).
These herbs may help prevent hypothermia. DO NOT give herbs or supplements to anyone who already has hypothermia.
- Panax ginseng (Panax ginseng). For preventing symptoms of cold exposure. You can also make teas from this herb. Panax ginseng may not be right for people with insomnia, autoimmune disease, schizophrenia, heart disease, bleeding disorders, hormone-related cancers, and others. Ginseng may interact with many medications including insulin, caffeine, Lasix, and others. Ginseng increases the risk of bleeding, especially if you also take blood thinners, such as warfarin (Coumadin), clopidogrel (Plavix), or aspirin. Panax ginseng is best prescribed by someone skilled in Chinese herbal medicine who can match appropriate herbs for your constitution. Ask your doctor before taking ginseng.
- Green tea (Camellia sinensis). For antioxidant, anti-inflammatory and cold protective effects. Use caffeine-free products. You may also make teas from the leaf of this herb.
- Bilberry (Vaccinium myrtillus). For antioxidant and vascular system support. Bilberry may increase the risk of bleeding, especially if you also take blood thinners, such as warfarin (Coumadin), clopidogrel (Plavix), or aspirin. People with low blood pressure, heart disease, diabetes, or blood clots should not take bilberry without first talking to their doctor. DO NOT take bilberry if you are pregnant or breastfeeding.
- Ginkgo (Ginkgo biloba). For antioxidant support and cold protection. Ginkgo interacts with many medications and can increase the risk of bleeding. People with diabetes, fertility problems, a history of seizures, or bleeding disorders may not be able to take ginkgo. If you take blood-thinning medication, such as warfarin (Coumadin) or aspirin, or any other medication, including birth control, talk to your doctor before taking ginkgo.
- Herbal teas. May help reduce symptoms of cold exposure.
Few studies have examined the effectiveness of specific homeopathic remedies. A professional homeopath, however, may recommend one or more of the following treatments for hypothermia based on their knowledge and clinical experience. Before prescribing a remedy, homeopaths take into account a person's constitutional type, including your physical, emotional, and intellectual makeup. An experienced homeopath assesses all of these factors when determining the most appropriate remedy for a particular individual.
- Aconitum. Very useful remedy when used just following exposure to cold, including in cases of shock and when extremities are cold, tingling, or numb.
- Arnica. Important homeopathic remedy for first aid, particularly in the case of shock and following trauma.
- Carbo vegetabilis. For icy cold, bluish skin, particularly when the person is weak, sluggish, close to fainting, and short of breath.
- Cuprum metallicum. For bluish discoloration of the skin accompanied by muscle cramps.
Prognosis and Possible Complications
People with mild hypothermia usually recover with no lasting damage. However, people with moderate-to-severe hypothermia can face serious complications and even death. Children are more likely to recover from severe hypothermia than adults. The death rate for hypothermia in older people is about 50%.
There are many possible complications from hypothermia, including:
- Hypoxia (lack of oxygen in the tissues)
- Frostbite leading to gangrene in the hands and feet
- Inflammation of the pancreas
- Fluid in the lungs
- Kidney failure
- Heart problems
People with severe hypothermia should be hospitalized. They may need CPR. They should be moved very carefully and watched closely for an irregular heartbeat, which could be fatal.
Normal body temperature in the elderly should be restored slowly, or permanent low blood pressure may result. All people with hypothermia must be watched closely until their body temperature returns to normal.
Ahlemeyer B, Krieglstein J. Neuroprotective effects of Ginkgo biloba extract. Cell Mol Life Sci. 2003;60(9):1779-1792.
Aslan L, Meral I. Effect of oral vitamin E supplementation on oxidative stress in guinea-pigs with short-term hypothermia. Cell Biochem Funct. 2007;25(6):711-715.
Beers MH, Porter RS, et al. The Merck Manual of Diagnosis and Therapy. 18th ed. Whitehouse Station, NJ: Merck Research Laboratories; 2006:2611-2613.
Bell DR, Gochenaur K. Direct vasoactive and vasoprotective properties of anthocyanin-rich extracts. J Appl Physiol. 2006;100(4):1164-1170.
Billeter AT, Hohmann SF, Druen D, Cannon R, Polk HC. Unintentional perioperative hypothermia is associated with severe complications and high mortality in elective operations. Surgery. 2014;156(5):1245-1252.
Blumenthal M, Goldberg A, Brinckmann J, eds. Herbal Medicine: Expanded Commission E Monographs. Newton, MA: Integrative Medicine Communications; 2000:106-109, 170-177.
Cabrera C, Artacho R, Gimenez R. Beneficial effects of green tea -- a review. J Am Coll Nutr. 2006;25(2):79-99.
Ferri FF, ed. Ferri's Clinical Advisor 2017. 1st ed. Philadelphia, PA: Elsevier; 2017.
Fontani G, Corradeschi F, Felici A, et al. Cognitive and physiological effects of Omega-3 polyunsaturated fatty acid supplementation in healthy subjects. Eur J Clin Invest. 2005;35(11):691-699.
Kimura K, Ozeki M, Juneja LR, Ohira H. L-Theanine reduces psychological and physiological stress responses. Biol Psychol. 2007;74(1):39-45.
Laniewicz M, Lyn-Kew K, Silbergleit R. Rapid endovascular warming for profound hypothermia. Ann Emerg Med. 2008;51(2):160-163.
LaValle JB, Krinsky DL, Hawkins EB, et al. Natural Therapeutics Pocket Guide. Hudson, OH: LexiComp; 2000:452-454.
Lavinio A, Timofeev I, Nortje J, et al. Cerebrovascular reactivity during hypothermia and rewarming. Br J Anaesth. 2007;99(2):237-244.
Park B, Lee T, Berger K, et al. Efficacy of nonpharmacological antishivering interventions: A systematic analysis. Crit Care Med. 2015;43(8):1757-1766.
Roberts JR, ed. Roberts and Hedges; Clinical Procedures in Emergency Medicine. 6th ed. Philadelphia, PA: Elsevier Saunders; 2014.
Rotsein OD. Oxidants and antioxidant therapy. Crit Care Clin. 2001;17(1):239-247.
Ruf T, Arnold W. Effects of polyunsaturated fatty acids on hibernation and torpor: a review and hypothesis. Am J Physiol Regul Integr Comp Physiol. 2008;294(3):R1044-R1052.
Simopoulos AP. Omega-3 fatty acids in inflammation and autoimmune diseases. J Am Coll Nutr. 2002;21(6):495-505.
Worfolk JB. Heat waves: their impact on the health of elders. Geriatr Nurs. 2000;21(2):70-77.
Yoon JH, Baek SJ. Molecular targets of dietary polyphenols with anti-inflammatory properties. Yonsei Med J. 2005;46(5):585-596.
Review Date: 11/20/2016
Reviewed By: Steven D. Ehrlich, NMD, Solutions Acupuncture, a private practice specializing in complementary and alternative medicine, Phoenix, AZ. Review provided by VeriMed Healthcare Network. Also reviewed by the A.D.A.M. Editorial team.