英文版https://en.wikipedia.org/wiki/Hypothermia
中文版https://zh.wikipedia.org/wiki/%E4%BD%8E%E4%BD%93%E6%B8%A9%E7%97%87
(原中文引言，歡迎參酌引用)
低體溫症，亦稱低溫症、失溫症，是生物體溫降到正常新陳代謝和生理機能所需溫度以下的症狀。對恆溫動物來說，核心體溫通常通過生物體內平衡被維持在一個恆定的水平上。但是，當身體暴露在寒冷的環境中時，這種內部機制可能無法再補充散失在環境中的熱量，從而造成低體溫症。
Hypothermia is defined as a body core temperature(人體溫度) below 35.0 °C (95.0 °F). Symptoms depend on the temperature. In mild hypothermia there is shivering and mental confusion. In moderate hypothermia shivering stops and confusion increases. In severe hypothermia there may be paradoxical undressing, in which a person removes his or her clothing, as well as an increased risk of the heart stopping(心搏停止).[2]
’’’失溫症’’’（{{lang|en|Hypothemia}}），又稱’’’低溫症’’’、’’’低體溫症’’’。描述當[[人體溫度|人體核心溫度]]低於35.0 °C（95.0 °F）時的現象。失溫症的症狀取決於溫度，輕度失溫可能造成{{le|發抖|Shivering}}與{{le|精神錯亂|Mental confusion}}；中度失溫的發抖症狀消失，但[[精神錯亂]]的狀況加重; 在重度失溫的情況下，會有{{le|反常脫衣現象|paradoxical undressing}}，也就是患者開始脫去衣物，這也同時增加了[[心搏停止]]的風險[2]。
Hypothermia has two main types of causes. It classically occurs from extreme exposure to cold.[1] It may also occur from any condition that decreases heat production or increases heat loss.[1] Commonly this includes alcohol intoxication(酒精中毒) but may also include low blood sugar(低血糖), anorexia(神经性厌食症), and advanced age, among others.[1][2] Body temperature(體溫調節) is usually maintained near a constant level of 36.5–37.5 °C (97.7–99.5 °F) through thermoregulation(體溫調節).[2] Efforts to increase body temperature involve shivering, increased voluntary activity, and putting on warmer clothing.[2][3] Hypothermia may be diagnosed based on either a person’s symptoms in the presence of risk factors or by measuring a person’s core temperature.[2]
失溫症主要有兩個造成原因，第一個最常見的是暴露在極低溫的環境中[1]，也有可能是處於任何一種會抑制體內產熱機制或增加失溫速度的情況下[1] 。這種狀態，多和[[酒精中毒]]脫不了干係，但可能在患有[[低血糖]]、[[厭食症]]、年老與其他不明原因下促使失溫症的產生[1][2]。身體的[[溫度調控]]恆定機轉理應將[[身體溫度]]維持在36.5到37.5°C （亦即97.7到99.5°F) 間[2]。顫抖、增加自發性運動的頻率以及穿上溫暖的衣物都有助於提高體內溫度[2][3]。失溫症的診斷主要是依據評估患者當下所處環境中危險因子可能引發的各項病徵，或是藉由量測病人的核心溫度所獲得[2]。
The treatment of mild hypothermia involves warm drinks, warm clothing and physical activity. In those with moderate hypothermia heating blankets and warmed intravenous fluids(靜脈注射) are recommended. People with moderate or severe hypothermia should be moved gently. In severe hypothermia extracorporeal membrane oxygenation(體外膜氧合) (ECMO) or cardiopulmonary bypassmay be useful. In those without a pulse(脉搏) cardiopulmonary resuscitation(心肺复苏) (CPR) is indicated along with the above measures. Rewarming is typically continued until a person’s temperature is greater than 32 °C (90 °F). If there is no improvement at this point or the blood potassium level is greater than 12 mmol/liter at any time resuscitation may be discontinued.[2]
輕微的失溫症可以用熱飲料、穿著暖和衣服及身體活動來改善。若是中等程度的的失溫症，建議使用加熱毯及注射加熱過後的[[靜脈注射|靜脈輸液]]。中等或是嚴重的失溫症病患需小心的移動。嚴重的失溫症病患可以用{{le|體外心肺循環|Cardiopulmonary bypass}}或是[[體外膜氧合]]（ECMO）。若已沒有[[脈搏]]需同時進行[[心肺復甦]]（CPR）。病人的復溫需持續到其體溫超過32 °C（90 °F）為止。若此時病情仍沒有改善，或是過程中血鉀濃度高於12 mmol/liter，此時可以停止心肺复苏術[2]。
Hypothermia is the cause of at least 1500 deaths a year in the United States.[2] It is more common in older people and males.[4] One of the lowest documented body temperatures from which someone with accidental hypothermia has survived is 13.0 °C (55.4 °F) in a near-drowning(遇溺) of a 7-year-old girl in Sweden.[5] Survival after more than six hours of CPR has been described.[2] In those in whom ECMO or bypass is used survival is around 50%.[2] Deaths due to hypothermia have played an important role in many wars.[1]Hyperthermia(中暑) is the opposite of hypothermia, being an increased body temperature due to failed thermoregulation.[6][7]
在美國，失溫症每年大約奪走1500條的生命[2]，患者多為老年人與男性[4] 。目前記錄中，失溫症患者所能達到的最低溫度是一名在瑞典因溺水而造成失溫的7歲女孩，她當時的體溫為13 °C (相當於55.4 °F)[5]，急救記錄中描述在經過超過六個小時的心肺復甦術(CPR)後她成功存活了下來[2] 。若過程中使用葉克膜或繞道手術，存活率大約是50%左右[2] 。戰爭中，失溫症常常是造成士兵死亡的重要死因[1]。和失溫症相對地疾病大概就是[[中暑]]了，該疾病的成因是由於體內溫度的調節系統失常而使得體溫不正常的升高[6][7]。