Overheating occurs when the body fails to regulate its heat level, resulting in heat injuries. Doctors at Singapore General Hospital (SGH), a member of SingHealth’s group of hospitals, explain that heat injuries are caused by the body’s inability to regulate its temperature properly.

The factors contributing to heat injuries

In Singapore’s hot and humid weather, heat injuries are a serious concern. It is important to recognize and treat heat injuries as soon as possible. However, you can easily and effectively prevent them by observing a few simple measures and knowing your limits.

Factors at play

There are a lot of factors that make you more likely to get heat injuries. In some cases, such as high temperatures, they are obvious, but in other cases, they are less obvious.

When exercising and training in the heat, there are several factors to consider.


  1. High temperatures – Heat is gained by the body through radiation when the air temperature is greater than 30-32 degrees Celsius.
  2. High humidity – Reduces sweat evaporation, resulting in less heat loss.
  3. Sun exposure – As a result of solar radiation, heat is gained in sunny weather. Cool, cloudy, and breezy weather reduces heat gain.
  4. Excessive strenuous physical activity – Repeated muscular contractions increase the body’s heat gain.
  5. Poor physical fitness, lack of sleep, obesity – Due to these factors, your cardiovascular system and sweat glands respond less efficiently to exercise, making you susceptible to heat injuries.
  6. Coffee, tea, alcohol – Water loss occurs through urination when these drinks are consumed.
  7. ​Certain medications – Sweating and urination may be reduced or increased by certain medications. If you are unsure, read the product insert or consult your doctor.
  8. ​Febrile illnesses – Change the body’s normal processes for regulating temperature.
  9. Illnesses that cause vomiting and diarrhoea – Fluid loss increases.

Heat injuries and their symptoms

Heat cramps are the mildest form of heat injury. The condition is caused by excessive sweating, which leads to a loss of water and salt. Larger muscle groups (calves, thighs, abdomen) experience painful intermittent muscle cramps.

The cardiovascular system is unable to cope with the metabolic demands of contracting muscles, leading to heat exhaustion, a severe form of heat injury. With elevated body temperature, the person experiences weakness, exhaustion, headaches, dizziness, and profuse sweating. It is important to treat heat exhaustion as soon as possible.

Heat stroke is the most severe form of heat injury, caused by a malfunctioning body’s temperature regulating mechanism, as evidenced by the body’s core temperature rising above 41 degrees Celsius and the absence of sweating. There is confusion and aggression in the person, and they may even slip into a coma. The symptoms of heat stroke are serious and require immediate medical attention! In the absence of proper medical attention, the person may die within minutes.


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