Hot and humid Singapore is "a perfect recipe" for heat injuries, say doctors.

In severe cases, this might lead to heatstroke, which can cause multiple organ failure and even death.

People become vulnerable to heat injuries with prolonged exposure to or physical exertion in hot environments, said Adjunct Associate Professor Roger Tian, a senior consultant sports physician at Changi General Hospital.

Children, people who are obese or on certain medications and workers who are not acclimatised to hot weather are at particular risk of heat injuries and should take extra precautions, said doctors.

This becomes even more important as average temperatures continue to rise. Last month, temperatures hit a high of 35 deg C on April 12, 13 and 25, according to Meteorological Service Singapore.

According to 2010 Singapore Armed Forces-Ministry of Health guidelines on heat injury management, six construction workers suffered heatstroke in 2009. Two died and one had permanent brain injury. Singapore sees about 150 cases of heatstroke a year, The Straits Times reported in 2012.

Heatstroke occurs when a person's body is unable to regulate its internal temperature, said Dr Wong Wei Mon, a senior family physician at Raffles Medical.

"The sweating mechanism, which functions to cool down the body, fails and the body's temperature rises rapidly," he said. "Hence, people can get into trouble pretty quickly if they are unaware of this phenomenon, especially those who suffer from chronic illnesses like diabetes and heart conditions."

Apart from heatstroke, other heat-related injuries could occur, said Dr Wong. They include heat cramps - acute, painful and involuntary muscle contractions that occur as a result of dehydration and electrolyte imbalances - and heat exhaustion.

Heat exhaustion may cause symptoms such as profuse sweating, nausea, vomiting, and headaches.

However, in the case of heatstroke, which occurs when the body temperature rises above 40 deg C, the body's sweating mechanism no longer works and the person might instead feel dry and hot.

Prevention is better than cure for heat injuries, said Dr Wong, adding that early recognition of symptoms could prevent a fatal event from occurring.

Preventive measures include proper hydration, wearing properly ventilated clothing and abstaining from exercise when unwell.

When faced with a heatstroke victim, doctors say the priority is to lower the person's body temperature. Move the person to a cool and shaded environment and call for help immediately.

The SAF said in a statement yesterday that when a solider suffers a heat injury, measures are taken to cool him, such as removing his clothes and applying ice or water on him.

The soldier is then taken to the nearest medical facility in camp to cool him further.

Once his condition has stabilised, the soldier is evacuated by ambulance to the nearest hospital for further treatment.