Heat exhaustion and heat stroke

The summer heat has been hard on everyone, but much more so on those who are suffering from chronic conditions such as cardiovascular disease. But even the healthy and fit need to take care.  The American Heart Association (AHA) especially warns us against two common health problems in the summer time: heat exhaustion and heat stroke.

Here are the symptoms of heat exhaustion:

• heavy sweating
• cold, clammy skin
• dizziness or fainting (syncope)
• a weak and rapid pulse
• muscle cramps
• fast, shallow breathing
• nausea, vomiting or both

If left unattended, heat exhaustion can quick progress to heat stroke, with the following symptoms:

• warm, dry skin with no sweating
• strong and rapid pulse
• confusion and/or unconsciousness
• high fever
• throbbing headaches
• nausea, vomiting or both

How do heat exhaustion and stroke happen?

Heat exhaustion and stroke can be caused by extreme temperatures and humidity on the one hand, and dehydration on the other hand. The AHA says that temperature above 70°F and humidity above 70% are conditions where heat stroke can happen. These extreme conditions can interfered with the natural cooling process of the body.

Dehydration plays an important role. Under these circumstances the body loses high amounts of fluids that need to be regularly and sufficiently replenished.

When you are dehydrated, your total blood volume decreases. The heart has to pump extra hard to get this smaller volume of blood to the vital parts of the body. In addition, dehydration can also lead to rise in body temperature that can cause damage to the heart and the brain.

So how can we avoid heat stroke and exhaustion?

Drink, drink, drink. The obvious preventive measure is to drink plenty of liquids to replenish what we lose. You may think you are drinking enough but it may not be sufficient at all. Here is a way to check whether you are dehydrated or not (source: AHA):

“A good way to monitor your body fluid level is to weigh every morning after using the bathroom. If you weigh two pounds less than normal in the morning, you’re probably dehydrated and need to drink more water before doing any vigorous physical activity. (You may have lost weight as water but not as fat.)”

Avoid strenuous physical activity outdoors in hot humid conditions. Exercising and working under these extreme conditions are simply asking for trouble. Last week, many construction works all over Zurich were put to a stop due to high temperatures. Those projects which chose to continue were required to provide shade to outdoor workers and frequent breaks up to 10 minutes every hour.

If you have to do sports outdoors, take precautions. Even the fittest athletes can suffer from heat exhaustion. It is therefore necessary to make sure your body is adapted to the conditions. Wear light, comfortable clothing during exercise. Do not forget to drink. If it really gets too hot, douse yourself with water.

Unfortunately, do not take the risks of extreme heat and humidity seriously. However, we must bear in mind: heat stroke can kill you!