Heat exhaustion and heatstroke - what's the difference?

Summer is upon us, and particularly with the end-of-year holidays coming up, we need to watch our exposure to the sun and heat.

On the Weekend Breakfast Doctor's Surgery slot, a listener asks Dr Charl van Loggerenberg to explain the difference between heat exhaustion and heatstroke.

As heat-related illnesses they are on the same spectrum, where the body essentially is slowly losing control of its thermostat, the Doc says.

He points out that our bodies possess the ability to manage our internal temperature irrespective of what is going on outside: 'We do that with behaviour; so, we can change our environment, our gear, the cooling around us and manage our temperature successfully quite nicely."

However, if at a certain point we start getting symptoms related to the elevated temperature, we enter the zone of a heat-related illness.

This usually affects our central nervous system, with symptoms like a drop in brain function and significant fatigue signalling a jump from heat exhaustion to heatstroke.

Heat exhaustion happens when the body overheats but can still control its temperature and is usually caused by activity in hot weather or by dehydration.

Heatstroke occurs when the body overheats to the point it can no longer cool itself and can signal a medical emergency.

"Heatstroke is Hyperthermia, where we're actually able to measure an elevated body temperature that is not fever related."

You can lower your risk of heat illness by staying hydrated and limiting physical activity in hot weather.

"It's very much about recognising the risk. You're not going to get this sitting in your office or driving about town. It's typically activity-related, and it doesn't have to be running the Comrades Marathon - it can just be excessive activity in an extremely warm and particularly humid environment, so it's really about monitoring your body carefully."

Click here to find out more about managing heat exhaustion and heatstroke.

To listen to Doctor's Surgery on CapeTalk's Weekend Breakfast, click on the audio link below (skip to 10:10 for discussion on heat-related illnesses):