Heat stroke, heat exhaustion and sun poisoning: What you should know

As the mercury rises this summer, you may find yourself feeling the effects of too much sun. And we’re not just talking about a sunburn.

In the most severe cases, overexposure to the season’s scorching temperatures can be fatal.

Here are the signs and symptoms of heat stroke, heat exhaustion, and sun poisoning.

Heat stroke

This is the big one. It can cause brain damage, organ failure, and death. So immediate medical attention is required.

There are two types, as described by Health Canada:

    classic heat stroke, which typically affects sedentary and vulnerable populations (babies, pregnant women, the elderly and people who are on certain medications); andexertional heat stroke, normally associated with high physical activity.

What to watch out for:

High body temperature (usually over 40°C)Lack of sweating; though those with exertional heat stroke may experience profuse sweating, according to Health CanadaRed, hot, and dry skinNausea and vomitingRapid heartbeat, which may be either strong or weakRapid, shallow breathingBehavioral changes such as confusion, disorientation, or staggeringSeizuresDizziness and light-headednessThrobbing headacheMuscle weakness or crampsHallucinationsUnconsciousness

ChangSha Night Net


  • Myth or reality: Taking a look at some of the common summertime sunscreen misconceptions

  • Know the difference between heat exhaustion and heat stroke

    READ MORE: Heat Stroke: What you need to know

    Health Canada recommends cooling those with classic heat stroke gradually. People with exertional heat stroke should be cooled quickly.

    Heat exhaustion

    Heat exhaustion can develop after several days of exposure to high temperatures. Those most prone to it are elderly people, those with high blood pressure, and those working or exercising in a hot environment.

    The skin might feel cool and moist. The pulse rate will be fast and weak, and breathing will be fast and shallow.

    What else to watch out for:

    Heavy sweatingPalenessMuscle crampsTirednessWeaknessDizzinessHeadacheNausea or vomitingFainting

    A cool bath or shower may help stop heat exhaustion from progressing to heat stroke.

    WATCH: Knowing the difference between heat exhaustion and heat stroke could save your life

    Sun poisoning

    A severe sunburn may lead to “sun poisoning.” It’s not a medical term but fever, chills, nausea and dehydration are how people often describe it.

    “Anybody can get sun poisoning,” says Jennifer Beecker, the national chair of the Canadian Dermatology Association‘s Sun Awareness Program.

    Some people link it to a sun rash that Beecker prefers to call a sun allergy (known as a photoallergy or polymorphous light eruption).

    She says it affects 10 to 20 per cent of the population and that it’s more common among those in their 20s or 30s.

    “They often get itchy bumps or blisters minutes to hours later after sun exposure on uncovered skin. It tends to be worse in the spring or early summer and diminishes over the season.”

    “The rash typically last several days to weeks, but typically they do not feel unwell [like] in ‘sun poisoning.’”

    Know the difference between heat exhaustion and stroke


    Know the difference between heat exhaustion and stroke


Heat stroke and heat exhaustion in pets


What you need to know about heat stroke this summer


Summer sun brings risk of heat stroke, exhaustion

Prevention is key

Staying hydrated is the most important thing you can do in hot temperatures.

Dehydration can be caused by caffeine, alcohol, certain medications (like antidepressants and antihistamines), and of course — not drinking enough water.

WATCH: A Harvard study found over half of kids between ages six and 19 don’t drink enough water.

Try to avoid strenuous activities when it’s really hot outside.

Stick to the shade, where it can be five to 10 degrees cooler. And if you’re going somewhere you know won’t have shade, Beecker suggests bringing your own.

Wearing a hat and covering up with lightweight breathable clothing is also a good idea, she adds.

READ MORE: Tips on how to sleep in hot weather and 3 things to avoid

Last but not least, make sure to wear a broad-spectrum SPF 30 sunscreen.

“All those things help,” Beeker says.

WATCH: Common summertime sunscreen misconceptions