Table of ContentsView AllTable of ContentsMechanismsAverage Body TemperatureThermoregulation DisordersCauses
Table of ContentsView All
View All
Table of Contents
Mechanisms
Average Body Temperature
Thermoregulation Disorders
Causes
Thermoregulation is how humans maintain a temperature range suitable for life. It is critical because having an extremely high or low internal temperature can ultimately cause severe symptoms likeseizures, unconsciousness, and even death.
For humans, the ideal temperature range for internal organs is around 98.6 degrees Fahrenheit (37 degrees Celsius). If the external environment threatens to raise or lower the core temperature, the body automatically takes steps to bring it back to normal through thermoregulation.
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The Three Mechanisms of Thermoregulation
Sensors (Thermoreceptors)
Thermoreceptors are specialized nerve parts that collect information about temperature. Some are sensitive to cold, and others to heat. Many are found in the skin, but others are located deeper inside the body, like inside the brain, spinal cord, or abdomen. These thermoreceptors send information to the hypothalamus.
Control Center (Hypothalamus)
Yourhypothalamusis the area of your brain that regulates several key bodily functions, including certain hormone levels, blood pressure, and temperature. It also integrates the sensory information coming in from your thermoreceptors.
If the incoming signals are too high or too low, the hypothalamus sends signals to fix this. It does this primarily through theautonomic nervous system, the system of nerves that control involuntary bodily functions.
Temperature Adjusters (Effectors)
Effectors are the parts of the body that respond to signals from the hypothalamus to lower or raise the core temperature. Effectors work in the following ways:
Additionally, the part of the brain that is more responsible for consciousness also receives signals to alert you, for example, to put on a sweater if you are cold or drink a glass of ice water if you are hot.
What’s an Average Internal Body Temperature?
Theaverage core body temperatureis around 98.6 degrees. However, this can vary a little between individuals and even within the same individual based on different factors like the time of day. Between 97.7 and 99.5 degrees is The typical baseline temperature for some people is between 97.7 and 99.5 degrees.
Your core body temperature is the temperature inside your head, chest, and abdomen. Notably, this temperature might vary significantly from the other parts of your body. For example, the temperature of your hands might be several degrees cooler.
Slightly Low Body TempSome people have a core body temperature thatruns a little low, making themprone to feeling cold, but their body temperature doesn’t technically qualify as hypothermia. A lower core temperature might be normal for some, but for others, it might be a sign of a medical condition like hypothyroidism.
Slightly Low Body Temp
Some people have a core body temperature thatruns a little low, making themprone to feeling cold, but their body temperature doesn’t technically qualify as hypothermia. A lower core temperature might be normal for some, but for others, it might be a sign of a medical condition like hypothyroidism.
Hyperthermia
Hyperthermia (increased body temperature in response to external factors) happens when the body cannot regulate itself with the external environment. It is different than afever, which occurs in response to an internal problem, like an infection.
In some cases, hyperthermia isn’t a big deal. For example, some healthy athletes can experience mild hyperthermia without health problems during intense exercise. However, higher temperatures can cause problems like muscle cramps and fainting. They can also increase the risk of dehydration and problems likeelectrolyte imbalancesandkidney damage.
Temperatures of 104 degrees and above can cause symptoms ofheat stroke, like confusion and seizures.The high temperature damages cells at a body temperature above 107 or 108 degrees and leads to to blood-clotting problems, organ failure, and eventually death.
Hypothermia
Inhypothermia, the body cannot keep up with lower surrounding temperatures, either because of an especially cold environment, internal changes (e.g., significant blood loss), or both.
Hypothermiais sometimes defined as a core temperature lower than 95 degrees. Once below 86 degrees or so, the person becomes unconscious, and their breathing and heart rate slow down. The heart stops at around 75 degrees, and death occurs.
In a very cold environment, your body shuttles more warm blood through your core and constricts blood flow to your extremities. This helps keep your core temperature up to keep you alive but also leaves you at risk offrostbite—significant damage to tissues from cold that might require amputation.
Therapeutic HypothermiaUnder certain circumstances, healthcare providers can actually use more mild forms of hypothermia as treatments to limit damage from certain health problems, including after some kinds of brain damage or during heart surgery.
Therapeutic Hypothermia
Under certain circumstances, healthcare providers can actually use more mild forms of hypothermia as treatments to limit damage from certain health problems, including after some kinds of brain damage or during heart surgery.
What Can Cause Thermoregulation Issues?
Extreme Weather
Exposure to very hot temperatures can lead to hyperthermia, especially if it lasts for prolonged periods. Similarly, sustained exposure to very cold weather can lead to hypothermia, especially if you don’t have proper clothes and equipment to protect you.
Some people experience hyperthermia from heat exposure, even in sedentary settings, such as an older individual living without air-conditioning during a heat wave—however, the risks of hyperthermia increase with exercise and lack of access to fluids. Exercise raises your internal temperature, so exercising during very hot weather increases the dangers of hyperthermia-related health issues like heatstroke.
Infection
Serious infections can lead tofever. Various substances in pathogens and immune components the body produces to respond to them can trigger fever. Some of these substances affect the way the hypothalamus and related structures operate, elevating the temperature set point.
Such fevers sometimes have a protective effect. For example, they may make the invader replicate less easily, or it may increase the effectiveness of other parts of the immune system. Individuals hospitalized for serious infections with mild to moderate fevers may tend to do better than those without fever.
In small children, high fevers can causefebrile seizures. These are alarming but hardly ever cause long-term problems. Fever itself is only rarely significantly harmful, although temperatures of 104 degrees and above can cause heat stroke symptoms. People hospitalized with very high fevers also tend not to do as well as those with mild or moderate fevers.
Age and Other Demographic Factors
Infants have some of the highest risks of environmental hypothermia and hyperthermia for a few reasons:
Although not as vulnerable as infants, preschoolers, and grade school children have higher risks than adolescents and older adults. Children are also more likely to have high fevers than adults. Older adults might not spike a fever even during some serious infections.
In general, very old individuals also have a higher risk of both environmental hypothermia and hyperthermia compared to younger adults, partly due to changes in various thermoregulatory mechanisms, body composition, medications, and their underlying health conditions.
The menstrual cycle can also affect baseline temperature. For example, your temperature tends to be higher in the time following ovulation. Pregnancy can make it more challenging to thermoregulate. And during menopause, you might experience brief periods when your internal temperature spikes (hot flashes).
Some of the most disadvantaged people are also more likely to experience problems from hypothermia or hyperthermia. For example, people with substance use disorder, those experiencing homelessness, and those living with mental illness are at increased risk because of factors like malnutrition, impaired ability to notice temperature changes, and their living situation.
Medications
Somemedicationsmay increase the risk of hypothermia or hyperthermia during extreme weather, especially for older and more frail individuals. This can happen, for example, if a medication makes you sweat less, decreases sensations of thirst, reduces blood vessel dilation or constriction, or decreases fluids in your body.
Examples are:
Additionally, certain medications can cause rare but potentially serious syndromes leading to hyperthermia even under normal environmental conditions.
For example, in malignant hyperthermia, body temperature can increase to a dangerously high temperature as an abnormal response to some medications used during anesthesia.Inneuroleptic malignant syndrome(a rare neurological disorder), you might get a very high fever and symptoms like muscle rigidity in response to certain antipsychotic medications.
Other Conditions
Various other conditions can also lead to overly high or low internal temperatures, some of which are:
Additionally, many chronic medical conditions that do not directly affect your internal temperature might make it harder for you to properly thermoregulate in response to environmental changes, like congestive heart failure, peripheral vascular disease, or anorexia nervosa.
Summary
Minor changes from your baseline temperature aren’t usually a big deal. However, various medical conditions and demographic factors, such as age, can increase your risk of more serious problems related to thermoregulation.
13 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Périard JD, Eijsvogels TMH, Daanen HAM.Exercise under heat stress: Thermoregulation, hydration, performance implications, and mitigation strategies.Physiol Rev. 2021;101(4):1873-1979. doi:10.1152/physrev.00038.2020Tansey EA, Johnson CD.Recent advances in thermoregulation.Adv Physiol Educ. 2015;39(3):139-148. doi:10.1152/advan.00126.2014Székely M, Garai J.Thermoregulation and age.Handb Clin Neurol. 2018;156:377-395. doi:10.1016/B978-0-444-63912-7.00023-0Maushart CI, Loeliger R, Gashi G, Christ-Crain M, Betz MJ.Resolution of hypothyroidism restores cold-induced thermogenesis in humans.Thyroid. 2019;29(4):493-501. doi: 10.1089/thy.2018.0436Walter EJ, Hanna-Jumma S, Carraretto M, Forni L.The pathophysiological basis and consequences of fever.Crit Care. 2016;20(1):200. doi:10.1186/s13054-016-1375-5Hifumi T, Kondo Y, Shimizu K, Miyake Y.Heat stroke.J Intensive Care. 2018;6:30. doi:10.1186/s40560-018-0298-4Paal P, Pasquier M, Darocha T, et al.Accidental hypothermia: 2021 update.Int J Environ Res Public Health. 2022;19(1):501. doi:10.3390/ijerph19010501Rathjen NA, Shahbodaghi SD, Brown JA.Hypothermia and cold weather injuries.Am Fam Physician. 2019;100(11):680-686.Tveita T, Sieck GC.Physiological impact of hypothermia: The good, the bad, and the ugly.Physiology (Bethesda). 2022;37(2):69-87. doi:10.1152/physiol.00025.2021Cramer MN, Gagnon D, Laitano O, Crandall CG.Human temperature regulation under heat stress in health, disease, and injury.Physiol Rev. 2022;102(4):1907-1989. doi:10.1152/physrev.00047.2021CDC.Heat and medications—guidance for clinicians.Rosenberg H, Pollock N, Schiemann A, Bulger T, Stowell K.Malignant hyperthermia: A review.Orphanet J Rare Dis. 2015;10:93. doi:10.1186/s13023-015-0310-1Ware MR, Feller DB, Hall KL.Neuroleptic malignant syndrome: Diagnosis and management.Prim Care Companion CNS Disord. 2018;20(1):17r02185. doi:10.4088/PCC.17r02185
13 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Périard JD, Eijsvogels TMH, Daanen HAM.Exercise under heat stress: Thermoregulation, hydration, performance implications, and mitigation strategies.Physiol Rev. 2021;101(4):1873-1979. doi:10.1152/physrev.00038.2020Tansey EA, Johnson CD.Recent advances in thermoregulation.Adv Physiol Educ. 2015;39(3):139-148. doi:10.1152/advan.00126.2014Székely M, Garai J.Thermoregulation and age.Handb Clin Neurol. 2018;156:377-395. doi:10.1016/B978-0-444-63912-7.00023-0Maushart CI, Loeliger R, Gashi G, Christ-Crain M, Betz MJ.Resolution of hypothyroidism restores cold-induced thermogenesis in humans.Thyroid. 2019;29(4):493-501. doi: 10.1089/thy.2018.0436Walter EJ, Hanna-Jumma S, Carraretto M, Forni L.The pathophysiological basis and consequences of fever.Crit Care. 2016;20(1):200. doi:10.1186/s13054-016-1375-5Hifumi T, Kondo Y, Shimizu K, Miyake Y.Heat stroke.J Intensive Care. 2018;6:30. doi:10.1186/s40560-018-0298-4Paal P, Pasquier M, Darocha T, et al.Accidental hypothermia: 2021 update.Int J Environ Res Public Health. 2022;19(1):501. doi:10.3390/ijerph19010501Rathjen NA, Shahbodaghi SD, Brown JA.Hypothermia and cold weather injuries.Am Fam Physician. 2019;100(11):680-686.Tveita T, Sieck GC.Physiological impact of hypothermia: The good, the bad, and the ugly.Physiology (Bethesda). 2022;37(2):69-87. doi:10.1152/physiol.00025.2021Cramer MN, Gagnon D, Laitano O, Crandall CG.Human temperature regulation under heat stress in health, disease, and injury.Physiol Rev. 2022;102(4):1907-1989. doi:10.1152/physrev.00047.2021CDC.Heat and medications—guidance for clinicians.Rosenberg H, Pollock N, Schiemann A, Bulger T, Stowell K.Malignant hyperthermia: A review.Orphanet J Rare Dis. 2015;10:93. doi:10.1186/s13023-015-0310-1Ware MR, Feller DB, Hall KL.Neuroleptic malignant syndrome: Diagnosis and management.Prim Care Companion CNS Disord. 2018;20(1):17r02185. doi:10.4088/PCC.17r02185
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Périard JD, Eijsvogels TMH, Daanen HAM.Exercise under heat stress: Thermoregulation, hydration, performance implications, and mitigation strategies.Physiol Rev. 2021;101(4):1873-1979. doi:10.1152/physrev.00038.2020Tansey EA, Johnson CD.Recent advances in thermoregulation.Adv Physiol Educ. 2015;39(3):139-148. doi:10.1152/advan.00126.2014Székely M, Garai J.Thermoregulation and age.Handb Clin Neurol. 2018;156:377-395. doi:10.1016/B978-0-444-63912-7.00023-0Maushart CI, Loeliger R, Gashi G, Christ-Crain M, Betz MJ.Resolution of hypothyroidism restores cold-induced thermogenesis in humans.Thyroid. 2019;29(4):493-501. doi: 10.1089/thy.2018.0436Walter EJ, Hanna-Jumma S, Carraretto M, Forni L.The pathophysiological basis and consequences of fever.Crit Care. 2016;20(1):200. doi:10.1186/s13054-016-1375-5Hifumi T, Kondo Y, Shimizu K, Miyake Y.Heat stroke.J Intensive Care. 2018;6:30. doi:10.1186/s40560-018-0298-4Paal P, Pasquier M, Darocha T, et al.Accidental hypothermia: 2021 update.Int J Environ Res Public Health. 2022;19(1):501. doi:10.3390/ijerph19010501Rathjen NA, Shahbodaghi SD, Brown JA.Hypothermia and cold weather injuries.Am Fam Physician. 2019;100(11):680-686.Tveita T, Sieck GC.Physiological impact of hypothermia: The good, the bad, and the ugly.Physiology (Bethesda). 2022;37(2):69-87. doi:10.1152/physiol.00025.2021Cramer MN, Gagnon D, Laitano O, Crandall CG.Human temperature regulation under heat stress in health, disease, and injury.Physiol Rev. 2022;102(4):1907-1989. doi:10.1152/physrev.00047.2021CDC.Heat and medications—guidance for clinicians.Rosenberg H, Pollock N, Schiemann A, Bulger T, Stowell K.Malignant hyperthermia: A review.Orphanet J Rare Dis. 2015;10:93. doi:10.1186/s13023-015-0310-1Ware MR, Feller DB, Hall KL.Neuroleptic malignant syndrome: Diagnosis and management.Prim Care Companion CNS Disord. 2018;20(1):17r02185. doi:10.4088/PCC.17r02185
Périard JD, Eijsvogels TMH, Daanen HAM.Exercise under heat stress: Thermoregulation, hydration, performance implications, and mitigation strategies.Physiol Rev. 2021;101(4):1873-1979. doi:10.1152/physrev.00038.2020
Tansey EA, Johnson CD.Recent advances in thermoregulation.Adv Physiol Educ. 2015;39(3):139-148. doi:10.1152/advan.00126.2014
Székely M, Garai J.Thermoregulation and age.Handb Clin Neurol. 2018;156:377-395. doi:10.1016/B978-0-444-63912-7.00023-0
Maushart CI, Loeliger R, Gashi G, Christ-Crain M, Betz MJ.Resolution of hypothyroidism restores cold-induced thermogenesis in humans.Thyroid. 2019;29(4):493-501. doi: 10.1089/thy.2018.0436
Walter EJ, Hanna-Jumma S, Carraretto M, Forni L.The pathophysiological basis and consequences of fever.Crit Care. 2016;20(1):200. doi:10.1186/s13054-016-1375-5
Hifumi T, Kondo Y, Shimizu K, Miyake Y.Heat stroke.J Intensive Care. 2018;6:30. doi:10.1186/s40560-018-0298-4
Paal P, Pasquier M, Darocha T, et al.Accidental hypothermia: 2021 update.Int J Environ Res Public Health. 2022;19(1):501. doi:10.3390/ijerph19010501
Rathjen NA, Shahbodaghi SD, Brown JA.Hypothermia and cold weather injuries.Am Fam Physician. 2019;100(11):680-686.
Tveita T, Sieck GC.Physiological impact of hypothermia: The good, the bad, and the ugly.Physiology (Bethesda). 2022;37(2):69-87. doi:10.1152/physiol.00025.2021
Cramer MN, Gagnon D, Laitano O, Crandall CG.Human temperature regulation under heat stress in health, disease, and injury.Physiol Rev. 2022;102(4):1907-1989. doi:10.1152/physrev.00047.2021
CDC.Heat and medications—guidance for clinicians.
Rosenberg H, Pollock N, Schiemann A, Bulger T, Stowell K.Malignant hyperthermia: A review.Orphanet J Rare Dis. 2015;10:93. doi:10.1186/s13023-015-0310-1
Ware MR, Feller DB, Hall KL.Neuroleptic malignant syndrome: Diagnosis and management.Prim Care Companion CNS Disord. 2018;20(1):17r02185. doi:10.4088/PCC.17r02185
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