While sunstroke requires direct exposure to the sun, heatstroke can occur even indoors if temperatures are high. — dpa
Wear a hat or cap, drink plenty of fluids, seek shade and avoid outdoor exercise.
These are the golden rules to get through hot days safely, without a sunstroke or heatstroke.
What’s the difference between the two anyway?
In both cases, high temperatures harm the body.
Put simply, ”sunstroke affects ‘only’ the head – that is, the brain. The rest of the body is fine,” says German Brain Foundation president Dr Frank Erbguth.
Heatstroke causes the body’s entire thermoregulation system to break down and can be fatal.
This doesn’t mean that sunstroke isn’t serious.
As Dr Erbguth points out, there’s often a seamless transition from it to heatstroke.
In contrast to heatstroke, however, sunstroke requires exposure to sunlight.
Heatstroke can also occur “in pitch darkness” if temperatures are very high, notes Dr Bernd Böttiger, head of the Department of Anaesthesiology and Intensive Care Medicine at Cologne University Hospital and federal coordinator of German Red Cross state doctors.
How heatstroke occurs
Our core body temperature is normally around 37°C.
Heat waves during which overnight temperatures remain high put the body under severe strain.
A point may be reached when it can’t cool down by sweating, particularly if you don’t drink sufficient fluids.
”The body is no longer able to dissipate heat,” explains Dr Erbguth.
So body heat builds and its core temperature rises to 40°C or more, which has consequences for various body systems.
“The coagulation and circulatory systems are the first to collapse,” he says.
It’s important to know in this regard that blood vessels dilate at high temperatures, increasing the flow of overheated blood to the skin, where heat is dissipated to the environment via the evaporation of sweat.
This cools both the skin and blood near its surface, which then flows at lower temperatures to deeper body regions.
But if heatstroke occurs, “blood coagulates,” says Dr Erbguth. “The small clots clog small blood vessels.”
The kidneys, along with the liver and heart, can no longer function properly.
At worst, this can lead to multiple organ failure.
”Humid heat is much worse than dry heat,” he adds, because increased water vapour in the air decreases evaporation of sweat on
the skin, and hence, the body’s ability to cool down.
Symptoms of heatstroke include sudden tiredness, headache and a vague feeling of dizziness, according to him.
“They can progress to nausea, vomiting, and then loss of consciousness.”
Dr Böttinger says that hot, dry skin and an accelerated heart rate are warning signals too.
Emergency measures
If you suspect someone has suffered heatstroke, it’s imperative to call the local emergency number.
Before paramedics arrive, you should get the affected person into the shade as quickly as possible, he advises.
Then you should cool the person’s body, but not by putting ice directly on the skin, which Dr Erbguth warns could cause frostbite.
Instead, wrap ice cubes and cold packs in a cloth first.
If the person is still conscious, you should offer them something to drink.
Dr Böttiger says water, as well as fruit tea or juice mixed with carbonated mineral water, are suitable.
Paramedics can give the person cooling intravenous infusions.
If the victim’s coagulation system has already collapsed, anticoagulants are administered in hospital.
In the case of sunstroke, “the meninges [thin layers of tissue that cover and protect the brain] and brain warm up.
"And an increase of just a degree or two is all it takes to cause a kind of meningitis [inflammation of the meninges],” says Dr Erbguth. “The brain isn’t the most robust of organs.”
At particular risk are people with no, little or very fine hair on their head, e.g. the elderly, babies and young children.
“The top of infants’ skull is thin,” points out Dr Böttiger.
Some sunstroke symptoms are similar to those of heatstroke, such as headache and dizziness.
Others can include neck pain and stiffness, sensitivity to light, and a flushed, hot head, he says.
Sometimes, symptoms may not appear until several hours after being out in the sun for quite some time, e.g. high fever in young children.
If you suspect someone might have sunstroke, you should get them out of the heat and to a cool place.
Their body should be cooled with wet cloths, and it’s best that their upper body be elevated.
They should also drink a lot of fluids.
If the person’s condition worsens and they start to lose consciousness, call your local emergency number. – dpa
