If someone becomes too hot and loses water and salt from the body, leading to tiredness, weakness and muscle cramps, this is referred to as heat exhaustion. If the body loses the ability to maintain the correct temperature and it becomes dangerously high, this is referred to as heatstroke.
Heat stroke generally occurs when an individual has been too hot for too long, whether working, exercising or simply sitting in a hot environment. If the body’s internal temperature reaches 40°C or higher, it is a potentially life-threatening condition.
High body temperature: an elevated body temperature is the main characteristic of heat stroke.
Mental changes: for instance, confusion, seizures (particularly in children), delirium, slurred speech, irritability and coma.
Sweat changes: in heatstroke brought on by hot weather, the skin will feel hot and dry. Heatstroke induced by physical exertion will leave the skin feeling moist.
Nausea: feeling sick or vomiting.
Headache: a throbbing headache is common with heatstroke.
Colour change: skin may turn red as the body becomes hotter.
Breathing: breathing might become quicker and shallower.
Heart rate: as the body attempts to cool down, the heart is put under increasing strain causing heart rate to rise.
Causes of exertional heatstroke: intense activity in a hot environment, whether exercise or work. Exertional heatstroke is more likely to occur if an individual is not used to high temperatures.
Causes of non-exertional or classic heatstroke: caused by exposure to a particularly hot environment. Classic heatstroke is most likely to occur if exposed to humid conditions for long periods of time. Those who are already sick are more susceptible, as are older people.
Exertion in high temperatures: anyone who is likely to be involved in intense activity in high temperatures is at risk.
Age: Extremes of age that is the young and the old are more susceptible to heat stroke.
Medications: medications like antidepressants, diuretics and beta blockers etc. can increase the risk of heatstroke by interfering with either the way the body responds to heat or by limiting the ability to stay hydrated.
Sudden exposure: at the beginning of a heat wave, or if visiting a much hotter climate, heatstroke is more likely to occur.
Medical conditions: ailments like heart and lung disease, obesity, gastroenteritis and a previous history of heat stroke can increase the risk of heat stroke.
Medical professionals can usually diagnose heatstroke from a person’s appearance and a discussion about their recent history. Medical tests like blood tests, urine tests, muscle tests, x-rays etc. will sometimes be ordered to rule out other potential causes.
The main aim of treating heatstroke is to lower the patient’s temperature to prevent further damage being done. There are a number of potential ways to achieve this:
Immersion: in cold water or an ice bath.
Evaporation cooling: cold water is misted onto the skin while warm air is fanned onto the body; this causes evaporation which cools the skin.
Cooling blankets and ice packs: cooling blankets are wrapped around the victim. Ice packs are placed in regions where large veins come close to the surface of the skin (groin, armpit, neck and back), ensuring that the blood rapidly reduces in temperature.
Muscle relaxants: drugs such as benzodiazepines may be given if the body temperature is not dropping; these prevent the body from shivering in response to the cold treatments.
Remaining cool and hydrated is essential. Below are some simple ways in which this can be achieved:
Clothing: wear loose-fitting, lightweight clothes – these allow the body to cool properly.
Fluids: maintain fluid intake to replace fluids lost through sweating.
Timing: take extra precautions during the hottest parts of the day (11 am to 3 pm). If it is not possible to cease activity, increase fluid intake and take frequent rests in the shade.
Sunburn: avoid being sunburned as this affects the way in which the body cools down.
Heatstroke is an underestimated condition that is completely avoidable if simple recommendations are followed. To summarise — on a hot day, wear loose clothes and have a cold drink while you sit calmly in the shade.