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.

What do I need to know about heat injuries?

Singapore is a hot and humid country with vivacious youths who lead active lifestyles and engage in physically strenuous sports such as football, basketball and kayaking. This means that heat injuries are a real concern here. 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 training and playing in the heat.

High temperaturesWhen air temperature is higher than 30-32 degrees Celsius, heat is gained by the body through radiation.
High humidityReduces sweat evaporation which leads to a decrease in heat loss through sweating.
Sun exposureIn 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 activityThis increases the body’s heat gain as a result of repeated muscular contractions.
Poor physical fitness, lack of sleep, obesityThese lower the efficiency of the cardiovascular and sweating responses to exercise, making you prone to heat injuries.
Coffee, tea, alcoholThese drinks actually increase the amount of water loss by increasing urination.
​Certain medicationsCertain medications may reduce sweating or increase urination. Read the product insert or check with your doctor if unsure.
​Febrile illnessesAlter the body’s normal temperature regulation processes.
Illnesses that cause vomiting and diarrhoeaIncrease fluid losses.​

Signs 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. This 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. This is a medical emergency! Without proper medical attention, the person can die within minutes.

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

Ref: V10​