Heat stroke? Try temperate water immersion

Sydney, November 18: Researchers from Wollongon University, New South Wales (NSW), Australia, suggest that the best thing you can do to treat a person suffering from heat stroke is immersing him/her in temperate water rather than using standard cold water bath as advised before.

Heatstroke, also called sunstroke, is a life-threatening condition which is caused by prolonged exposure to very hot temperatures or dehydration and can also be caused if the body's own temperature regulation mechanism fails to work properly. It could lead to coma and possibly death.

Lead author of the study, Prof. Nigel Taylor of Wollongon University, NSW, Australia, said, "Cooling in temperate water took only marginally longer than that in cold water, and one cannot imagine that the 45 secs cooling difference would have any meaningful physiological or clinical implications."

The study which appears in the journal Medicine and Science in Sports and Exercise, found that immersing person suddenly in cold water may actually shut down the blood supply to the skin and make it difficult for heat to dissipate from the body of the victim.

People who spend more time working out in sun or doing vigorous physical activity in hot weather especially sports persons, miners, and soldiers with heavy protective clothing often causes dangerous overheating.

And once a person’s core temperature reaches 39.5°C (Celsius) to 40.5°C (Celsius) they get hyperthermia, a general name given to a variety of heat-related illnesses. The medical response to hyperthermia is to cool the body as soon as possible by immersing the victim in cold water (about 14 degree Celsius).

Dr. Matt Brearley, sports scientist of the Northern Territory Institute of Sport, says that at this temperature "most of the bodily processes will start to break down" and people lose their ability to regulate blood flow properly and can even stop sweating , which means they store more heat at the time when they most need to dissipate it. And a person's failure to control blood pressure generally leads to collapse, he added.

Brearley said, “Then they're in grave danger because they're actually threatening their life."

For the study, Professor Taylor and colleagues studied eight males, who were heated to temperature of 39.5 degree celsius, as measured by a sensor inserted into the oesophagus. The participants did physical exercise in 36°C and 50 percent relative humidity while wearing a suit with 40°C hot water pumping through it.

They compared the data on how long it took the subjects to cool down in 20-22°C air, 14°C water and 26°C water and found that there was hardly any difference between the effects of cold and temperate water.

According to study author the temperate water has a 'less drastic affect' on the skin’s blood supply than cold water and this compensates for the fact that it is not as cold.

Dr Matt Brearley agrees that it may be more practical to use temperate water rather than cold water to cool people with hyperthermia. However, he added that it is too soon to recommend changes for heat stroke treatment and would like to see more data in this field.

The symptoms of heat stroke are abdominal cramps, fatigue, dizziness, vomiting, nausea, muscle cramps, headache and heavy sweat or a lack of sweat in a hot climate. Elderly people, children, pregnant or breastfeeding women, overweight people and people with heart disease or high blood pressure are most at risk of heat strokes.