Related articles
High temperature inhibits bacterial and viral growth and speeds the body's reaction for killing organisms and repairing tissue.
Fever begins when infecting organisms and the immune response cause the body's set point for temperature to be raised. The anterior hypothalamus in the brain controls many body activities, most of which are related to homeostasis (balance). One such function is heat-loss and heat-production. However, when an infection is present, the control mechanism is turned up and maintained until micro-organisms are eliminated.
Imagine that the thermometer was reset to 103°F (39.4°C). The autonomic nervous system responds by causing physical changes designed to raise the body's core temperature to the new setting. Firstly the pores of the skin as well as the blood vessel walls are constricted to keep heat in. Adrenalin production is increased, which in turn stimulates metabolism to speed heat-production. At the same time, the nervous system causes increased muscle tone, so that an involuntary stretch and contraction occurs in rapid succession. This induces shivering. So the cold skin and shivering, called a chill, is the body's method of raising its core temperature. When it reaches 103°F the chill goes, because no further heat increase is required. However, this temperature is maintained until the infection is destroyed. At this stage the heat-loss centre in the hypothalamus is activated to return the body temperature to normal. Heat is lost by relaxation of the muscle fibers in blood vessel walls and dilation of the pores of the skin.
The fever, besides inhibiting toxins, also clears waste from the tissues, lymph and blood, on which bacteria feed and multiply. Iron is used up in retarding bacterial growth during fever, but the temperature needs to be very high to kill microbes. It is not the heat alone at work, rather that the raised temperature stimulates an increased immune response. Killer T-cells are increased, as are neutrophils and macrophages, which are the white blood cells responsible for destroying invaders. At the same time, tissue-repairers like fibroblasts and collagen are formed at an increased rate.
Sometimes the thermometer appears to be set too high, and only then do we intervene to lower the temperature to a reasonable level by natural means. Studies have shown that children receiving antibiotics treatment have fevers of longer duration that those on placebo, and considerably longer than those on herbal teas and bed rest alone. Putting out the flame prematurely reduces the response to an infection which is still present. Studies have also shown that infections requiring urgent treatment will respond to fever-reducing drugs faster than less serious diseases. This may induce a false sense of security, especially in the case of smouldering meningitis, because the fever is gone but the disease remains.
So what is a safe level of fever? 103°F (39.4°C) is generally acceptable in adults, and at this level immune response is enhanced. However, in a child of six months or less, it is too high and must be reduced. The cause also needs immediate investigation. Infants cannot localise infections easily, and so infections are more likely to spread at this age and precipitate meningitis. Serious note must be taken of any localising signs or symptoms accompanying fever, such as a stiff neck or joints, and medical treatment should be sought immediately.
It is thought that the body has a built-in mechanism that limits fever to 106°F (41.1°C), which a healthy adult body can tolerate for several hours. Cells do not die off until 110°F (43.3°C) is reached. However, if a patient fasts on water alone, it is rare for a fever to go over 104°F (40°C). Individual safety margins must be assessed, because much has to do with a person's normal vitality levels. In some diseases, such as cancer, fever is deliberately induced to raise core temperature and stimulate the immune system to destroy malignant cells. This destruction begins at 106°F (41. 1°C).
Outline of fever management
1. Assist the fever to natural completion so that it is resolved as quickly as possible.
2. Intervene only if the temperature is over 101°F (38.3°C) in an infant, 103°F (39.4°C) in a child or 104°F (40°C) in an adult, or if there is some other health factor which contraindicates fever, such as pregnancy, heart disease or low vital energy.
3. Never use aspirin, and only reach for paracetamol if the temperature stays too high for more than two hours in an infant, or six hours in a child, in spite of natural interventionist methods.
4. Prevent dehydration.
5. Strengthen the immune system in the long term.