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For most folks, a thermometer reading around 98.6 degrees Fahrenheit (37 degrees Celsius) means their body temperature is normal. Now, two scientists have an idea why our bodies, as well as those of most other mammals, consistently run at that temperature : A toasty body temperature helps keep nasty fungal infections at bay. "One of the mysteries about humans and other advanced mammals has been why they are so hot compared with other animals," said study co-author Arturo Casadevall, professor and chair of microbiology and immunology at Albert Einstein College of Medicine of Yeshiva. "This study helps to explain why mammalian temperatures are all around 98.6 degrees Fahrenheit." Casdevall's previous work showed that the number of fungal species that can thrive and, therefore, infect an animal declines by 6 percent for every 1.8 degree F (1 C) rise in temperature. This, he claimed, is why reptiles , amphibians and other cold-blooded animals are susceptible to tens of thousands of fungal species, whereas only a few hundred types of fungi can harm humans and other mammals. In Casadevall's recent study, published in the journal mBio, he and his collaborator, biologist Aviv Bergman, also of Einstein College of Medicine, analyzed the fungus-fighting benefits gained by a maintaining a body temperature between 86 and 104 F (30 and 40 C) against the costs it takes a lot of food to keep the fire burning that hot. The optimal temperature, it turned out, was 98.06 F (36.7 C), just a hair away from what we consider "normal" for humans. (It might be even closer to normal, given that many scientists now consider 98.2 F (37.77 C) to be the true normal temperature for humans.) There is a range around the optimal calculation where different mammals have settled depending on their specific needs, but most advanced mammals have temperatures in the 96.8 to 104 F range (36 to 40 C), Casadevall told Life's Little Mysteries. For example, at 104 degrees Fahrenheit, rabbits are much hotter than humans and other mammals are a bit colder. One downside of a higher body temperature is of the amount of food it takes to keep the fire burning. Still, maintaining a warmer body could have provided the critical edge mammals needed to outlast the dinosaurs. The asteroid reset things by killing off dinosaurs and large animals, Casadevall said. The mammals were then able to become the predominant animals (beating the surviving reptiles) because they were warm-blooded, and thus not susceptible to many fungal diseases.
Got a question? Send us an email and we'll look for an expert who can crack it. Follow Bjorn Carey on Twitter @thebjorncarey Bjorn Carey is the science information officer at Stanford University. He has written and edited for various news outlets, including Live Science's Life's Little Mysteries, Space.com and Popular Science. When it comes to reporting on and explaining wacky science and weird news, Bjorn is your guy. He currently lives in the San Francisco Bay Area with his beautiful son and wife. Thermoregulation is the biological mechanism responsible for maintaining a steady internal body temperature. The thermoregulation system includes the hypothalamus in the brain, as well as the sweat glands, skin, and circulatory system. The human body maintains a temperature of about 98.6°F (37°C) using various physical processes. These include sweating to lower the body temperature, shivering to raise it, and narrowing or relaxing blood vessels to alter blood flow. If an individual is unable to regulate their temperature, they could overheat, leading to hyperthermia. The opposite is also true: If the core temperature falls below a safe level, it will cause hypothermia. Both conditions can potentially be life threatening. This article explores thermoregulation and how this essential process works. It also covers thermoregulation disorders and their possible causes. Thermoregulation is how mammals maintain a steady body temperature. Unlike reptiles, which have a body temperature that changes with their environment, mammals need to keep a consistent body temperature all of the time. In humans, the healthy range is within a degree or two of 98.6°F (37°C). When thermoregulation works as it should, the body performs at its optimum level. A temperature that is too high or too low can affect the:
The human body uses three mechanisms of thermoregulation:
Efferent responses are the behaviors that humans can engage in to regulate their own body temperature. Examples of efferent responses include putting on a coat before going outside on cold days and moving into the shade on hot days. Afferent sensing involves a system of temperature receptors around the body to identify whether the core temperature is too hot or cold. The receptors relay the information to the hypothalamus, which is part of the brain. The hypothalamus acts as the central control, using the information it receives from afferent sensing to produce hormones that alter body temperature. These hormones send signals to various parts of the body so that it can respond to heat or cold in the following ways: The healthy temperature range for the human body is very narrow. If the body cannot maintain a temperature within this range, thermoregulation disorders can develop. HyperthermiaHyperthermia occurs when the body’s heat-regulating mechanisms fail, and the body temperature becomes too high. There are several types of hyperthermia, including:
The symptoms of heat exhaustion are:
Heatstroke causes similar symptoms, but with some important differences, including:
Learn more about the differences between heat exhaustion and heatstroke. HypothermiaHypothermia occurs when the body loses heat faster than it can produce it. Prolonged exposure to cold temperatures can cause hypothermia. The symptoms include:
In young children and babies, hypothermia causes cold skin, which may be bright red in those with light skin tones. Several factors can affect thermoregulation, including environmental conditions, diseases, and certain medications. Extreme weatherExtreme weather can significantly affect the body’s ability to regulate temperature. Hypothermia occurs when a person has exposure to extremely cold temperatures for an extended period. In these instances, the body loses heat quickly, and heat production cannot keep up, causing a dip in body temperature. In addition to freezing temperatures, hypothermia can also occur in cool temperatures if sweat, rain, or submersion in cold water chills someone. On the opposite end of the spectrum, hot weather and extended exposure to the sun can cause the body to overheat. Instead of losing more heat than it can produce, the body heats up faster than it can cool itself down. Someone may also develop hyperthermia in warm temperatures as a result of:
InfectionsWhen a person has an infection, harmful microorganisms invade the body and multiply. These pathogens can thrive at typical body temperatures, but an increased temperature makes it more difficult for some of them to survive. For this reason, part of the immune response to infections is often a fever. This occurs when the body raises its own temperature in an effort to kill infection-causing organisms. Many doctors recommend letting a fever run its course so that the body can adequately protect itself. However, problems can arise if the body temperature becomes too high, hindering necessary functions. If someone has a fever above 105°F (40.5°C) that does not decrease with medication, they should seek urgent medical attention. A doctor will treat the fever to try to lower the body temperature to a safe level. AgeInfants and older adults have a higher risk of thermoregulation disorders. The reason for this is that these individuals have a lower muscle mass, a decreased shiver reflex, and lower immunity. Older adults tend to have a lower body temperature and may not develop fevers when they contract a viral or bacterial illness. Sometimes, they can develop hypothermia instead. Other diseasesOther diseases can also affect thermoregulation. These include: Endocrine disordersThe endocrine system comprises glands and organs that produce hormones, such as the pancreas, thyroid, pituitary gland, and adrenal glands. If something interferes with hormone production, it can affect body temperature. For example, an underactive thyroid, or hypothyroidism, can lead to a lower body temperature, while an overactive thyroid, called hyperthyroidism, can cause a higher body temperature. Central nervous system (CNS) disordersThe CNS includes the brain, spinal cord, and nerves. Conditions that affect the CNS can interfere with thermoregulation by impairing afferent sensing and central control. Some examples of these conditions include:
MedicationsCertain medications can disrupt thermoregulation as a side effect, causing a temporary rise in body temperature. Some people refer to this as “drug fever.” Examples of medications that can have this effect include:
Usually, thermoregulation quickly returns to normal when a person stops taking the drug. People should always speak with a doctor before changing the dosage of their medication. Mammals use thermoregulation to keep the body within a tight temperature range. This is essential for health, as it allows organs and bodily processes to work effectively. If a person’s body temperature strays too far from 98.6°F (37°C), they can develop hyperthermia or hypothermia. Various factors can contribute to this, including infections, extreme weather, medications, and other health conditions. Thermoregulation disorders can be a medical emergency. If a person has symptoms of hypo- or hyperthermia, it is important to dial 911 or the number of the nearest emergency department. Why is the body temperature maintained at about 37 C?It is important that we maintain an optimum temperature for the enzymes in our body (around 37 degrees celsius). If it's too hot, our enzymes will denature and will become inactive/lose their function. If it's too cold, the enzymes will too become ineffective (their function will slow down too much).
Why is the body temperature maintained at about 37 C quizlet?Because chemical reactions occurring in cells are very heat sensitive. A temperature of 37°C is the optimum for cellular reactions. Increased body temperature can cause nerve malfunction, change in the structure of proteins and death.
Why is it important for your body temperature to be maintained at a certain level?Body temperature must be controlled within a very narrow range so that the body can function properly. In particular, enzymes in a body's cells must have the correct temperature to be able to catalyse chemical reactions.
Why do you need to maintain a stable internal temperature of 98.6 degrees Fahrenheit about 37 degrees Celsius )?The body's core internal temperature has a narrow range and typically ranges 97-99 F with tight regulation. When the body's ability to thermoregulate becomes disrupted it can result in overheating (hyperthermia) or being too cool (hypothermia).
Why is the optimum temperature 37?For the enzymes in our bodies, optimum temperature is around 37∘ . Another reason for maintaining body temperature at 37∘ is that if the body is too hot, it will lose water more easily (it will evaporate) leading to a higher risk of dehydration. It also take a lot of energy to heat the body.
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Why is the body temperature maintained at about 37 degree Celsius instead of some other temperature?
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