Basal body temperature is the lowest temperature the body reaches during rest or sleep. It can be measured as soon as an individual has woken up and before any physical activity has taken place. Basal body temperature varies greatly in women during different pints in the meststrual cycle and can be used in family planning as an indicator of ovulation and peak days for conception.

If the temperature of the body is found to be too high or too low, the person may be suffering from Hyperthermia or Hypothermia respectively or a fever.  The body maintains a set temperature through regulation by the Hypothalamus (part of the brain that controls the body temperature).   A raise in this set point results in a fever, which is usually an indicator or a disease or infection that the body is fighting.  When the body temperature is raised without the consent of the hypothalamus, it is known as Hyperthermia.

Hyperthermia occurs when the body absorbs more heat than it is able to dissipate. It is usually brought about by lengthy exposure to high temperatures. The heat regulating mechanisms of the body will become overwhelmed and cause temperature to climb.  Once the body reaches 40 C (104 F), immediate medical treatment is required. Symptoms of Hyperthermia include confusion, fatigue and headache and dry, red skin. Mild hyperthermia is known as heat exhaustion while severe hyperthermia is called heat stroke.

Treatment for Hyperthermia involves rehydration and cooling the body.  This can be achieved through moving out of direct sunlight indoors or into a shaded area, drinking water, removing articles of clothing that may be keeping heat on the body or simply washing exposed skin with cool water.

Hypothermia occurs when body temperature falls below the norm that is needed for metabolic reactions and bodily functions to be carried out. It is usually a result of prolonged exposure to cold water or air.

Instruments for measuring body temperature

Glass or thermometers

These can be placed under the armpit or under the tongue to find measure body temperature. Breaking a glass thermometer in the couth can be dangerous as the contents (mercury or alcohol) can be poisonous.

Electronic thermometers

Are made from solid plastic and use a metallic sensor to measure temperature. They have a digital display field and are easy to read.

Plastic thermometer strip

Can be placed on the forehead to give local reading. This measurement can be affected by the surrounding temperature

Ear thermometers

Measure body temperature by using infrared head emission in the ear. This takes only one second making them very popular for use with children.