Heat stroke: The damaging effects of heat stroke

When the daily high temperatures hover around 30 degrees Celcius for a few days in a row, you know what to do.

But we can't always stay indoors, camped out in front of an air conditioning vent. So if you do have reason to spend an extended period outside in the heat and suddenly feel nauseous or disoriented, it's time to take IMMEDIATE steps to cool your body because a heat stroke can be just as dangerous as an ischaemic stroke. And don't buy that line that only older people are vulnerable - a heat stroke doesn't discriminate by age.

Heat wave takes its toll
Last month, some areas of India experienced consecutive daytime highs well above 43 degrees Celcius, easily qualifying the summer of 2005 as one of the hottest ever on the Indian sub-continent. The worst part is the toll taken by heat stroke and dehydration: Official reports put the number of deaths at about 200, but the actual count may be quite a bit higher.

As tragic as that is, it's not as bad as the Chicago heat wave of 1995 in the US, in which more than 600 people died over a period of nine days. The true severity of that weather event is put into perspective by the low temperatures: Over one two-day stretch the low didn't dip below 31 degrees. How rare is that? Meteorologists say there's less than a 1 percent chance of it ever happening again.

Most of us will never have to endure a heat wave like the recent one in India or the Chicago grilling of a decade ago. But a 1998 study that used data gathered from the Chicago incident reveals that the effects of heat stroke can have long-term consequences that sometimes turn deadly.

Kidney problems, blood clots and lung malfunction are all side effects of heat stroke
American researchers from the University of Chicago Medical Centre followed 58 subjects chosen from more than 3,000 patients with heat-related conditions who were admitted to Chicago area hospitals between July 12 and July 20, 1995. All 58 subjects experienced symptoms of near-fatal heat stroke. Each was interviewed at the time of their discharge from the hospital, with a follow up interview scheduled one year later.

Almost a full quarter of the subjects died within the year; most of them within the first three months. All of the remaining survivors suffered some amount of brain and nervous system impairment. Approximately half were diagnosed with kidney problems and blood clots, while 10 percent of the group experienced malfunction of the lungs due to inflammation. After taking into account each subject's health conditions before hospitalisation, all of these side effects were judged to be a direct result of heat stroke.

Perhaps the most significant finding was that age was not a factor among the subjects who died, in spite of the fact that the elderly are generally at greater risk of suffering heat stroke. Subjects ranged in age from 25 to 95, with the average age of the group being around 67.

The study also recognised the fact that because of overcrowded conditions in all of the participating hospitals during this crisis, the immediate care - which is critical - was not as comprehensive as it should have been, underlining how important it is to quickly seek medical attention when the first signs occur.

Know the symptoms
You probably already know the basic advice for avoiding heat-related health problems: Limit direct sun exposure, eat light meals, drink plenty of water, avoid dehydrating beverages such as alcohol and coffee, and wear light clothing.

Beyond that good advice it's useful to know the warning signs: Skin may become flushed accompanied by headache, nausea, disorientation and heavy sweating. As the body temperature rises the skin will become hot and dry and sweating will stop. As soon as these symptoms appear the victim must be cooled immediately, either with air conditioning, fans, or with lukewarm water. Cold water should not be used because it may cause shivering which raises body temperature.

To further avoid heat-related problems, add a little fruit juice containing vitamin C to your water. This will increase your level of antioxidants that can help protect cells and muscles from dehydration damage.

Replacing electrolytes that are lost when you sweat is a primary concern also. Electrolytes are electrically charged ions that your cells need to carry electrical impulses to other cells to maintain muscle and nerve control. In most heat-related situations you won't need to worry about electrolytes if you're getting enough water. But if you begin to feel weak from dehydration you should look for a beverage containing sodium, potassium and magnesium, all of which can help replenish electrolytes. Sports drinks usually contain these minerals, but they also typically contain sugar and flavorings. So if you must resort to a sports drink, it's a good idea to dilute it with water.

Most importantly, you simply can't neglect your body's hydration cycle. Optimize conditions that allow sweat to evaporate while constantly replacing the fluids lost through sweating.