“Body temperature regulation is primarily controlled by the hypothalamus, a region of the brain that acts as the body’s thermostat.” Whimsy columnist CLIVE WILLIAMS wonders if hot-blooded people really are.

“I tried to give blood the other day. But the blood bank wouldn’t take it. They wanted to know where I got it from.” –Wally Wang (writer and software expert)

Some people are described as hot blooded – but is there much of a temperature variation between individuals, and is your body temperature important?

The fact is that the human body maintains a remarkably stable internal temperature, which is critical for optimal physiological functioning. 

The average body temperature is approximately 37 degrees Celsius (98.6 degrees Fahrenheit), although it can vary slightly based on individual factors, time of day, and activity levels. This equilibrium, known as homeostasis, is essential for the myriad biochemical reactions that sustain life.

Body temperature regulation is primarily controlled by the hypothalamus, a region of the brain that acts as the body’s thermostat. When the body senses changes in external or internal conditions, the hypothalamus triggers mechanisms to restore balance. 

For instance, when the body becomes too warm, sweat glands produce perspiration, which cools the skin through evaporation. Conversely, when the body is too cold, mechanisms such as shivering and vasoconstriction (narrowing of blood vessels) conserve heat and generate warmth.

This regulation is vital because enzymes, the proteins that facilitate biochemical reactions, operate optimally within a narrow temperature range. Significant deviations from the average temperature can impair enzyme function, leading to disruptions in metabolic processes. 

For example, if the body becomes too cold (hypothermia), enzyme activity slows down, which can affect the heart, brain and other vital organs. On the other hand, excessive heat (hyperthermia) can denature enzymes, effectively halting critical chemical reactions and causing cellular damage.

As mentioned, enzymes are highly temperature sensitive. The human body’s temperature provides an ideal environment for these proteins to catalyze reactions efficiently. Any significant deviation can impede processes such as digestion, energy production, and DNA replication.

Body temperature also plays a crucial role in the immune system’s ability to fight infections. Fever, a temporary increase in body temperature, is a defence mechanism that creates an inhospitable environment for pathogens. It also enhances the efficiency of white blood cells, aiding in the elimination of harmful micro-organisms.

Proper body temperature is essential for the optimal function of the nervous system. Nerve impulses, which rely on ion exchanges across cellular membranes, are sensitive to temperature changes. Extremes of heat or cold can impair these signals, leading to symptoms such as confusion, slowed reflexes, or even loss of consciousness.

During physical activity, maintaining an appropriate body temperature is critical. If the body overheats, it can lead to heat exhaustion or heat stroke, conditions that can be life-threatening. Conversely, exposure to extreme cold without adequate protection can result in hypothermia, which impairs muscular and cardiovascular performance.

The human body’s cells are composed of lipids, proteins, and nucleic acids that function within a specific temperature range. Extreme deviations can compromise cell membranes and protein structures, leading to tissue damage or systemic failure.

Several factors can influence body temperature, including age, activity level and environmental conditions. Infants and the elderly are more vulnerable to temperature extremes due to less efficient thermoregulatory mechanisms. Physical activity generates heat, raising body temperature temporarily, while exposure to cold environments can lower it.

Additionally, hormonal changes, such as those during menstruation or pregnancy, can cause fluctuations in body temperature. Illnesses, particularly infections, often lead to fever as the body combats pathogens.

To maintain a stable body temperature, it’s essential to adapt to environmental conditions appropriately. In hot climates, staying hydrated, wearing lightweight clothing, and seeking shade can prevent overheating. In cold environments, layering clothing and consuming warm fluids help retain body heat.

Medical interventions are sometimes necessary to address temperature extremes. For hypothermia, gradual warming techniques, such as warm blankets or heated intravenous fluids, are employed. For hyperthermia, cooling methods, including ice packs or cooling blankets, are used to lower body temperature safely.

The human body’s temperature is a cornerstone of health and survival. Its regulation ensures that vital processes occur efficiently, protecting the body from the detrimental effects of extreme temperatures. 

To end where we started, I’ve been told I’m hot and it seems that resting individuals can have a slight difference in temperature range, meaning one person’s baseline body temperature might be 36.5°C while mine could be 37.5°C.

On a lighter note: Paul went to the doctor for his annual check-up. Apart from scratches on his arms and legs he was in great shape. 

“Do you work out?” asked the doctor. 

“Well,” said Paul, “I spend a lot of time running up and down slopes, beating through the bush and diving in lakes.” 

“My gosh,” said the doctor, “that’s impressive – you’re training to be an ironman?

“No,” says Paul. “I’m just a very poor golfer”.

Clive Williams is a Canberra columnist.