question: How does a single degree(C°) make such a large difference when it comes to fevers?
comment: Lots of natural processes are substantially affected by small differences in temperature. Water won't freeze at 1C, but will freeze at 0C, for example. It might seem odd that small changes can make such a big difference, since a difference of one degree in the air temperature doesn't usually feel like a huge difference. But, consider that part of the reason one degree doesn't usually feel like a lot is because your body has a ton of mechanisms that are working 24/7 to keep your core body temperature where it needs to be, compensating for whatever temperature swings are happening around you. If you didn't have your body's internal heating and cooling systems, trust me, one degree Celsius would feel like a huge difference.. Life and death, even.
passages: A wide range for normal temperatures has been found. Central temperatures, such as rectal temperatures, are more accurate than peripheral temperatures.
  
  Fever is generally agreed to be present if the elevated temperature is caused by a raised set point and:
  
  BULLET::::- Temperature in the anus (rectum/rectal) is at or over
  
  BULLET::::- Temperature in the mouth (oral) is at or over
  
  BULLET::::- Temperature under the arm (axillary) or in the ear (tympanic) is at or over
   In healthy adults, the range of normal, healthy temperatures for oral temperature is , for rectal it is , for tympanic membrane (the ear drum) it is , and for axillary (the armpit) it is . Harrison's Principles of Internal Medicine defines a fever as a morning oral temperature of 37.2 °C (98.9 °F) or an afternoon oral temperature of 37.7 °C (99.9 °F) while the normal daily temperature variation is typically 0.5 °C (0.9 °F).
   With fever, the body's core temperature rises to a higher temperature through the action of the part of the brain that controls the body temperature; with hyperthermia, the body temperature is raised without the influence of the heat control centers.
  
  Section::::Concepts.:Hypothermia.
  
  In hypothermia, body temperature drops below that required for normal metabolism and bodily functions. In humans, this is usually due to excessive exposure to cold air or water, but it can be deliberately induced as a medical treatment. Symptoms usually appear when the body's core temperature drops by below normal temperature.
  
  Section::::Concepts.:Basal body temperature.
   To counter this, Francesco Torti, who first systematically studied the effect of cinchona in the treatment of malaria, wrote a book which he titled "Therapeutice Specialis ad Febres Periodicas Perniciosas".
  
  Section::::Tree of fevers.
   A temperature "setpoint" is the level at which the body attempts to maintain its temperature. When the setpoint is raised, the result is a fever. Most fevers are caused by infectious disease and can be lowered, if desired, with antipyretic medications.
  
  An early morning temperature higher than or a late afternoon temperature higher than is normally considered a fever, assuming that the temperature is elevated due to a change in the hypothalamus's setpoint. Lower thresholds are sometimes appropriate for elderly people. The normal daily temperature variation is typically , but can be greater among people recovering from a fever.
   Continuous fever
  
  Continuous fever is a type or pattern of fever in which temperature does not touch the baseline and remains above normal throughout the day. The variation between maximum and minimum temperature in 24 hours is less than 1°C (1.5°F). It usually occurs due to some infectious disease. Diagnosis of continuous fever is usually based on the clinical signs and symptoms but some biological tests, chest X-ray and CT scan are also used. Typhoid fever is an example of continuous fever and it shows a characteristic step-ladder pattern, a step-wise increase in temperature with a high plateau.
  
  Section::::Examples.
   where,
  
  Or
  
  where,
  
  It is also acceptable to approximate this relationship for occupants engaged in near sedentary physical activity (with metabolic rates between 1.0 met and 1.3 met), not in direct sunlight, and not exposed to air velocities greater than 0.10 m/s (20 fpm). 
  
  where formula_5 and formula_6 have the same meaning as above.
  
  Section::::Application.
   Section::::Temperature regulation.
   Fever is an important feature for the diagnosis of disease in domestic animals. The body temperature of animals, which is taken rectally, is different from one species to another. For example, a horse is said to have a fever above (). In species that allow the body to have a wide range of "normal" temperatures, such as camels, it is sometimes difficult to determine a febrile stage.
   "This established patient has had a fever with sore/scratchy throat and severe headache for the past three days. He has had a little nausea but no vomiting. He said his pain is relieved with cold drinks and ibuprofen.
   Consider a village where all villagers are either healthy or have a fever and only the village doctor can determine whether each has a fever. The doctor diagnoses fever by asking patients how they feel. The villagers may only answer that they feel normal, dizzy, or cold.
   Cost benefit trade-off actuary issues apply to the antibacterial and antiviral effects of fever (increased body temperature). Fever has the future benefit of clearing infections since it reduces the replication of bacteria and viruses. But it also has great present metabolic (BMR) cost, and the risk of hyperpyrexia. Where it is achieved internally, each degree raise in blood temperature, raises BMR by 10–15%. 90% of the total cost of fighting pneumonia, goes, for example, on energy devoted to raising body temperature. During sepsis, the resulting fever can raise BMR by 55%—and cause a 15% to 30% loss of body mass. Circumstances in which fever deployment is not selected or is reduced include:
   Section::::Variation in animals.:Variations due to fever.
  
  Fever is a regulated elevation of the set point of core temperature in the hypothalamus, caused by circulating pyrogens produced by the immune system. To the subject, a rise in core temperature due to fever may result in feeling cold in an environment where people without fever do not.
  
  Section::::Variation in animals.:Variations due to biofeedback.
  
  Some monks are known to practice Tummo, biofeedback meditation techniques, that allow them to raise their body temperatures substantially.
  
  Section::::Low body temperature increases lifespan.
   Temperature depression (hypothermia) also needs to be evaluated. It is also noteworthy to review the trend of the patient's temperature. A fever of 38 °C is not necessarily indicate an ominous sign if the patient's previous temperature has been higher.
  
  Section::::Primary vital signs.:Pulse.
   Fever, also known as pyrexia and febrile response, is defined as having a temperature above the normal range due to an increase in the body's temperature set point. There is not a single agreed-upon upper limit for normal temperature with sources using values between . The increase in set point triggers increased muscle contractions and causes a feeling of cold. This results in greater heat production and efforts to conserve heat. When the set point temperature returns to normal, a person feels hot, becomes flushed, and may begin to sweat. Rarely a fever may trigger a febrile seizure. This is more common in young children. Fevers do not typically go higher than .
   If fever-reducing drugs lower the body temperature, even if the temperature does not return entirely to normal, then hyperthermia is excluded.
  
  Section::::Prevention.
   Normal body temperatures vary depending on many factors, including age, sex, time of day, ambient temperature, activity level, and more. A raised temperature is not always a fever. For example, the temperature of a healthy person rises when he or she exercises, but this is not considered a fever, as the set point is normal. On the other hand, a "normal" temperature may be a fever, if it is unusually high for that person. For example, medically frail elderly people have a decreased ability to generate body heat, so a "normal" temperature of may represent a clinically significant fever.
  
  Section::::Diagnosis.:Types.
   A degree day is computed as the integral of a function of time that generally varies with temperature. The function is truncated to upper and lower limits that vary by organism, or to limits that are appropriate for climate control. The function can be estimated or measured by one of the following methods, in each case by reference to a chosen base temperature:
  
  BULLET::::- Frequent measurements and continuously integrating the temperature deficit or excess;
   In general, higher temperatures will require lower relative humidities to achieve thermal comfort compared to lower temperatures, with all other factors held constant.  For example, with clothing level = 1, Metabolic rate = 1.1, and air speed 0.1 m/s, a change in air temperature and mean radiant temperature from 20 degrees C to 24 degrees C would lower the maximum acceptable relative humidity from 100% to 65% to maintain thermal comfort conditions.  The CBE Thermal Comfort Tool can be used to demonstrate the effect of relative humidity for specific thermal comfort conditions and it can be used to demonstrate compliance with ASHRAE Standard 55-2017.
   Unexplained statements in the Hippocratic writings, Cleghorn argued, become clear in the light of clinical observations on the Mediterranean coasts, and the context that diseases, both acute and chronic, are there often modified by malarial fever. The pathology of enteric fever and acute pneumonia was unknown in at the time, but the book gives an account of the course of enteric fever complicated with tertian ague, with dysentery, and with pneumonia. His own misconceptions did not seriously cloud what he observed at the bedside. Four editions were published during the author's lifetime, and a fifth with some alterations in 1815.
   An organism at optimum temperature is considered "afebrile" or "apyrexic", meaning "without fever". If temperature is raised, but the setpoint is not raised, then the result is hyperthermia.
  
  Section::::Concepts.:Hyperthermia.
   The temperature can be measured in various locations on the body which maintain a fairly stable temperature (mainly sub-lingual, axillary, rectal, vaginal, forehead, or temporal artery). The normal temperature varies slightly with the location; an oral reading of 37 °C does not correspond to rectal, temporal, etc. readings of the same value. When a temperature is quoted the location should also be specified. If a temperature is stated without qualification (e.g., typical body temperature) it is usually assumed to be sub-lingual. The differences between core temperature and measurements at different locations, known as "clinical bias", is discussed in the article on normal human body temperature. Measurements are subject to both site-dependent clinical bias and variability between a series of measurements (standard deviations of the differences). For example, one study found that the clinical bias of rectal temperatures was greater than for ear temperature measured by a selection of thermometers under test, but variability was less.
   Body temperature is normally tightly regulated to about 37 °C (98.6 °F), with women being slightly warmer than men.
  
  The Consortium is perhaps best known for perioperative thermoregulation, with members having published far more on the subject than all other investigators combined.
  
  In a series of several hundred studies, for example, Consortium members identified dose-dependent effects of every major anesthetic
  
  and sedative
  
  on thermoregulatory control, and consequent alterations in heat balance.
  
  Impaired temperature control, combined with a cold operating room environment, makes most unwarmed surgical patients hypothermic by 1-3 °C.
   BULLET::::- c = 2.33854883889
  
  BULLET::::- c = -0.14611605
  
  BULLET::::- c = -0.012308094
  
  BULLET::::- c = -0.0164248277778
  
  BULLET::::- c = 0.002211732
  
  BULLET::::- c = 0.00072546
  
  BULLET::::- c = -0.000003582
  
  An alternative set of constants for this equation that is within ± of the NWS master table for all humidities from 0 to 80% and all temperatures between and all heat indices below is:
  
  A further alternate is this:
  
  where
  
  For example, using this last formula, with temperature and relative humidity (RH) of 85%, the result would be: .
  
  Section::::See also.
  
  BULLET::::- Apparent temperature
  
  BULLET::::- Humidex
  
  BULLET::::- Wet-bulb temperature
  
  BULLET::::- Wind chill
   Temporal artery thermometers, which use the infrared principle report temperature, are becoming increasingly common in clinical practice because of their ease of use and minimal invasiveness. Because of the variability of technique and environmental considerations, measurements by temporal artery thermometers may suffer issues of precision, and to a lesser degree accuracy. Temporal thermometers have been found to have a low sensitivity of around 60–70%, but a very high specificity of 97–100% for detecting fever and hypothermia. Because of this, it is suggested that they should not be used in acute care settings like the ICU, or in patients with a high suspicion of temperature imbalance. Evidence supports higher accuracy and precision amongst pediatric patients. 
  
presuppositions: A single degree of temperature has particular significance when measuring a fever. A single degree is not a huge difference for your body.
corrections: A single degree of temperature can generally substantially affect many natural processes. One degree Celsius would be a huge difference for your body, potentially life and death.
raw_presuppositions: A single degree of temperature has particular significance when measuring a fever. A single degree is not a huge difference for your body.
raw_corrections: A single degree of temperature can generally substantially affect many natural processes. One degree Celsius would be a huge difference for your body, potentially life and death.