Hypothermia results from an abnormally low body temperature, which causes the circulatory, respiratory, and nervous systems to slow down. Body temperature is a balance between how much heat is produced and how much heat is lost, with the brain acting as the thermostat. Severe hypothermia can cause an irregular heartbeat, which can lead to heart failure and possibly death. Over 700 deaths occur annually from hypothermia in the United States.

The following signs and symptoms accompany hypothermia:

• Skin that is cold to the touch
• Absence of 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

Hypothermia can happen from accidental exposure to cold, to immersion in cold water, or to trauma from a serious accident. In the elderly, hypothermia may develop over hours or days as a result of poor body heat regulation, inability to properly sense the cold, or living in a cold environment in the winter. Diseases of the endocrine glands also may result in decreased heat production in the body.

The following factors can cause hypothermia:

• Exposure to cold
• Immersion in cold water
• Severe trauma, especially brain injury or burns
• Immobilization (not moving for long periods)
• Age-related physical problems: half of all hypothermia-related deaths occur in people over age 65
• Pre-existing disease such as heart failure, pulmonary infection, other toxic infections, or endocrine disorders
• Dehydration
• Drugs such as alcohol, tranquilizers, sedatives, hypnotics, or antipsychotics
• Poverty, malnutrition, or homelessness
• Social isolation or mental illness

Severe hypothermia is a life-threatening condition. If you or someone you care for is experiencing symptoms associated with hypothermia that cannot be easily reversed, call the Emergency Assistance Number, 9-1-1, immediately.

Hypothermia can usually be prevented by preparing appropriately for environmental conditions and by recognizing the early symptoms. If you plan to be outdoors for extended periods in cold weather, wear insulated or layered moisture-wicking clothing, including headgear. Avoid overexertion, eat enough food, drink enough fluids, and do not drink alcohol. People who are prone to hypothermia, such as the elderly or the homeless, can receive assistance from social service agencies to help them find adequate housing, heat, and clothing.

Mild hypothermia can be treated by warming the person. Wet clothing should be removed and replaced with dry, warm clothing and/or blankets. Other techniques include using hot water bottles, warm baths, or heat packs placed under the arms and on the chest, neck, and groin. In severe cases, if breathing and heartbeat have stopped, the person should not be considered dead until efforts have first been made by medical professionals to warm him or her.

At the hospital, the medical team will use heated intravenous fluids. The person may be wrapped with blankets in a warm room or put into a large tub of warm water.

In severe or complicated cases of hypothermia, intravenous drug therapy may be used.

Nutritional measures can help prevent hypothermia. Animal studies suggest that Western and Chinese herbal therapies influence body temperature and may help prevent hypothermia if used before, or just after, exposure to cold. Depending on results from future scientific studies, they may also help treat hypothermia. If you become hypothermic, avoid supplements and herbs, such as ginseng, hawthorn, rosemary, and possibly cocoa seed and yellow Jessamine root, that dilate your blood vessels and may worsen hypothermia. Similarly, stimulation of specific acupuncture points may cause hypothermia.

Eating enough calories in the form of proteins and fats before and during exposure to cold weather may help prevent hypothermia, particularly in the elderly. If you expect to be exposed to the cold, carry high-calorie snacks, such as protein bars and nuts. Regular intake of fluids—water, juices, and electrolyte replacement drinks—is important, too, and prevents dehydration. Being dehydrated increases your risk for hypothermia. Do not wait until you are hungry or thirsty to eat or to drink fluids. Don't drink alcohol or caffeine, as these substances dilate your blood vessels and increase blood flow away from your central core, causing it to cool down.

Ginseng (Eleutherococcus senticosus and Panax ginseng) has not been studied in relation to hypothermia; however, it is known as an adaptogen (a substance that helps to rebuild strength and regenerate the body after stress or fatigue). It is used to increase resistance to adverse conditions such as unusually cold climate. It may help prevent hypothermia in people who are regularly exposed to extreme cold weather, in the elderly, and in those who are weak or have a chronic disease.

An Indian herbal preparation containing Winter cherry (Withania somnifera), Asparagus (Asparagus racemosus), Giant potato root (Pueraria tuberosa), Velvet bean (Mucuna pruriens), Yam (Dioscorea bulbifera), Elephant creeper (Argyreia speciosa), Long pepper (Piper longum), and asphalt (a mixture of plant and microbial waste products) was given to rats to control hypothermia. As a result, the rats were better able to use fatty acids to generate extra energy and regulate their body temperature. The early results from these rat studies raise questions about whether this herbal combination may help prevent hypothermia in humans when used before or after cold exposure, or help treat the early phases of hypothermia. (Note: Although single herbs are available in health food stores, it is best to get combinations of herbs from a practitioner trained in Ayurvedic medicine. Ayurveda is the oldest existing medical system in the world, practiced primarily in India.)

Frequently, warming the extremities occurs after the warming of the core in treating hypothermia. A Chinese herbal medicine, called TSGS-to in Japanese, was tested in rats, and was effective in raising the heat radiating from the rats' tails. The formula contained the herbs Angelica root (Angelicae radix), Cinnamon bark (Cinnamomi cortex), Evodia fruit (Evodiae fructus), Licorice (Glycyrrhizae radix), dried ginger (Zingiberis rhizoma), Akebia (Akebiae caulis), Jujubae (Zizyphi fructus), Asiasarum root (Asiasari radix), and Peony root (Paeoniae radix). The researchers concluded that this particular combination of herbs may prove useful for hypothermic patients whose extremities often remain cold despite warm conditions and improved core temperatures.

Certain herbs used in Traditional Chinese Medicine (TCM) may cause hypothermia. For instance, rats given Clerodenron fragrans (Ventenaceae) became hypothermic in moderate and cold temperatures because their bodies produced less heat. Also, rat studies show that TCM remedies used to treat fever, such as Huang chin (Chinese Skullcap; Scutellaria baicalensis George), may cause hypothermia.

There have been few studies examining the effectiveness of specific homeopathic remedies. A professional homeopath, however, may recommend one or more of the following treatments for hypothermia based on his or her knowledge and clinical experience. Before prescribing a remedy, homeopaths take into account a person's constitutional type. In homeopathic terms, a person's constitution is his or her 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

Caution must be exercised when using acupuncture to treat fever. Stimulating certain acupuncture points with needles can produce hypothermia by decreasing the heat from metabolism (chemical processes in your body) and by dilating blood vessels in the skin.

Massage should not be used in the case of hypothermia. Massage may dilate the blood vessels on the surface of the body, drawing blood away from the core and vital organs such as the heart and the brain. During hypothermia, this may cause your circulatory system to collapse.

People with mild hypothermia have an excellent prognosis. 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 mortality rate for hypothermia in the elderly is about 50%. There are many possible complications from hypothermia, including hypoxia (lack of oxygen in the tissues), gangrene in the hands and feet, inflammation of the pancreas, fluid in the lungs, pneumonia, kidney failure, and heart irregularities.

Those who have severe hypothermia should be hospitalized; if necessary, cardiopulmonary resuscitation will be performed. A hypothermic patient should be transported very carefully as there is a tendency toward irregular heartbeat that 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 closely monitored until their body temperature returns to normal.

Beers MH, Berkow R, eds. The Merck Manual of Diagnosis and Therapy. Whitehouse Station, NJ: Merck & Co. 1999:2451-2452, 2507-2508.

Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Boston, Mass: Integrative Medicine Communications; 1998:138-139, 142-143, 148-149, 197.

Blumenthal M, Goldberg A, Brinckmann J, eds. Herbal Medicine: Expanded Commission E Monographs. Newton, Mass: Integrative Medicine Communications; 2000:106-109, 170-177.

Centers for Disease Control and Prevention. Hypothermia-related deaths: Georgia, January 1996–December 1997, and United States, 1979–1995. MMWR Morb Mortal Wkly Rep. 1998;47:1037-1040.

Cummings S, Ullman D. Everybody's Guide to Homeopathic Medicines. 3^rd ed. New York, NY: Penguin Putnam; 1997: 297, 318-319.

Decker W. Hypothermia. In: Adler J, et al. eds. Emergency Medicine: An On-line Medical Reference. Accessed at www.emedicine.com on January 19, 2000.

Hayward JS, Eckerson JD, Kemna D. Thermal and cardiovascular changes during three methods of resuscitation from mild hypothermia. Resuscitation. 1984;11:21-33. 

Jonas WB, Jacobs J. Healing with Homeopathy: The Doctors' Guide. New York, NY: Warner Books; 1996: 254-258.

Kanai S, Okano H, Abe H. Efficacy of Toki-shigyakuka-gosyuyu-syokyo-to (Danggui-sini-jia-wuzhuyu-shengjiang-tang) on peripheral circulation in autonomic disorders. Am J Chin Med. 1997;25(1):69-78.

Kumar R, Grover SK, Shyam R, Divekar HM, Gupta AK, Srivastava KK. Enhanced thermogenesis in rats by a composite Indian herbal preparation-I and its mechanism of action. J Altern Complement Med. 1999;5(3):245-251.

Lin MT, Chandra A, Chen-Yen SM, Chern YF. Needle stimulation of acupuncture loci chu-chih (LI-11) and ho-ku (LI-4) induces hypothermia effects and analgesia in normal adults. Am J Chin Med. 1981;9(1):74-83.

Lin MT, Ho ML, Chandra A, Hsu HK. Serotoninergic mechanisms of the hypothermia induced by Clerodenron fragrans (Ventenaceae) in the rat. Am J Chin Med. 1981;9(2):144-154.

Lin MT, Liu GG, Wu WL, Chern YF. Effects of Chinese herb, Huang chin (Scutellaria baicalensis George) on thermoregulation in rats. Jpn J Pharmacol. 1980;30(1):59-64.

Murray JE, Pizzorno MT, eds. Textbook of Natural Medicine. Edinburgh: Churchill Livingstone; 1999: 531.

Weinberg AD. Hypothermia. Ann Emerg Med. 1993;22 (Pt 2):370-377.

Semenza JC, McCullough JE, Flanders WD, McGeehin MA, Lumpkin JR. Excess hospital admissions during the July 1995 heat wave in Chicago. Am J Prev Med 1999;16(4):269-277. 

Ullman D. The Consumer's Guide to Homeopathy. New York, NY: Penguin Putnam; 1995: 326.

Worfolk JB. Heat waves: their impact on the health of elders. Geriatric Nursing: American Journal of Care for the Aging. 2000;21(2):70-77.