Heat injuries arise from the failure of the body to properly regulate its heat level, resulting in overheating. "Heat injuries refer to a spectrum of medical conditions which arise from the failure of the body to properly regulate its heat level, resulting in overheating," say ​doctors from Singapore General Hospital (SGH), a member of the SingHealth​ group.

Factors contributing to heat injuries

Heat injuries are a real concern with Singapore's hot and humid weather. Heat injuries can kill if they are not recognised and treated early. Most importantly, by observing a few simple measures and knowing your limits, they can be effectively and easily prevented.

Predisposing factors

A number of contributing factors increase your chances of suffering from heat injuries. Some of them are obvious, like high temperatures, while others are less so.

Below is a list of factors to be aware of when exercising and training in the heat.

High temperatures

When air temperature is higher than 30-32 degrees Celsius, heat is gained by the body through radiation.

High humidity

Reduces sweat evaporation which leads to a decrease in heat loss through sweating.

Sun exposure

In sunny weather, there is heat gain from solar radiation. There is less heat gain when the weather is cloudy, cool and breezy.

Excessive strenuous physical activity

This increases the body’s heat gain as a result of repeated muscular contractions.

Poor physical fitness, lack of sleep, obesity

These lower the efficiency of the cardiovascular and sweating responses to exercise, making you prone to heat injuries.

Coffee, tea, alcohol

These drinks actually increase the amount of water loss by increasing urination.

​Certain medications

Certain medications may reduce sweating or increase urination. Read the product insert or check with your doctor if unsure.

​Febrile illnesses

Alter the body’s normal temperature regulation processes.

Illnesses that cause vomiting and diarrhoea

Increase fluid losses.​

Types of heat injuries and symptoms

A heat cramp is the mildest form of heat injury. It occurs due to excessive loss of water and salt, caused by profuse sweating. Painful intermittent muscle cramps are experienced in the larger muscle groups (calves, thighs and abdomen).

Heat exhaustion is a severe form of heat injury, and is a sign that the cardiovascular system is unable to cope with the metabolic demands of contracting muscles. The person experiences weakness, exhaustion, headaches, dizziness and profuse sweating with elevated body temperature. Heat exhaustion requires prompt treatment.

Heat stroke, the severest form of heat injury, represents failure of the body’s temperature regulating mechanism, as evident by the core body temperature rising above 41 degrees Celsius and decreased or absence of sweating (which is a very serious sign). The person appears confused and aggressive, and may even slip into a coma. Heat stroke is a medical emergency! Without proper medical attention, the person can die within minutes.

See page 2 for tips to prevent overheating​.​​

Ref: V10

Check out other articles on exercise injuries:

Remedies for Common Running Injuries

How to Prevent Running Injuries

6 Ways to Relieve Muscle Pain After Exercise

What Causes Running Cramps?

Achilles Pain: What Causes It and How to Treat

Common Knee Injuries: Ligament, Tendon and Cartilage

Why You Shouldn't Ignore Running Injuries