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Keep it cool

Live Better / July 2015

The summer sun isn’t all fun and games. Learn the signs of heat exhaustion and heatstroke

Numbers vary depending on annual temperatures, but several hundred Canadians each year (about 120 people in major cities like Toronto and Montreal) will die from heat-related causes, with children and seniors in the category of most susceptible. And further to that, a study by Toronto Public Health and Environment Canada predicts heat-related deaths could double by 2050 and triple by 2080 due to global warming.

The projected fatality statistic is scary, but the good news is heat-related illnesses—or hyperthermia, which ranges from a mild heat rash through heat exhaustion and finally heatstroke—are preventable, just by taking care in the sun and by recognizing early symptoms before they progress.

Heat exhaustion is a warning the body is getting too hot. “The main features would be a body temperature lower than 40°C [or 104°F], with potential thirst, nausea, vomiting, sweating and/or clammy skin and weakness,” says Dr. Shannon French, a doctor specializing in paediatrics in Kingston, Ont. “The person may have slight confusion, dry lips and tongue, increased heart rate and dizziness.” Sweaty skin indicates the body is still working to cool itself. Treatment for heat exhaustion includes stopping activity, relocating to a cool, shady environment and rehydrating appropriately. In extreme cases, intravenous fluids and hospital admission may be necessary.

“Heatstroke is much more serious and dangerous,” explains Dr. French. “It occurs after the body’s cooling mechanisms have failed.” Heatstroke can present very similarly to heat exhaustion, although the main differences are a likelihood of higher internal temperatures (above 40°C) and the possibility of altered mental status: “Patients with heatstroke will have high temperatures, dry skin instead of sweaty skin and will frequently have abnormal mental symptoms, such as slurred speech, hallucinations, persistent confusion and seizures,” she says.

Heatstroke is a medical emergency that can be fatal, so immediately notify emergency services and cool the person by whatever means necessary such as a cool shower or applying ice packs. As for the many and varied symptoms leading up to heatstroke, “there are no hard and fast rules for when to go to the hospital, especially with kids,” says Dr. French. Children and babies are at a greater risk for dehydration, and may not be able to tell you their symptoms, so always err on the side of caution and contact a health practitioner, just in case.

“Symptoms of heat exhaustion and heatstroke should never be ignored,” says Dr. French, though they can easily be overlooked on hot summer days. Avoid heat-related illness by wearing loose clothing that breathes, staying hydrated and taking breaks from the weather in cool, shady areas.