Why is your health at risk during a heat wave?

Many places in Europe are experiencing their hottest recorded June. This week there was a record temperature of 38.6 degrees Celsius in Germany.

The national meteorological authorities in Belgium, the Czech Republic, France, Germany, Italy, Spain, and Switzerland have issued warnings of heat, advising people to avoid strenuous activities during the warm hours of the day, drink plenty of water and stay away from the sun.

There are different ways to put your health at risk during a heat wave. This is what you should know and how to protect yourself.

How your body reacts to heat

After exposure to high temperatures, many people will suffer mild and temporary side effects, such as nausea, dizziness, and fatigue, said Owen Landeg, a senior environmental public health scientist at the Public Health Agency of England.

"The important thing, however, is that at that time we can all take measures to prevent the most severe effects of the heat," Landeg said.

This includes heat exhaustion, which happens you get very hot and your body loses water or salt. Symptoms include headaches, weakness, muscle cramps and feelings of fainting or illness. 

Heat exhaustion could lead to heat stroke, a much more serious condition, according to the Public Health Agency of England.

Heat stroke is less common, but more dangerous than heat exhaustion. It happens when the temperature of your body increases above 40 degrees Celsius.

At the same time, you also experience profound changes in brain function: "Alterations in consciousness or mental state," Dr. Corey Slovis, professor and president of emergency medicine at Vanderbilt University Medical Center, told CNN in 2017. With a heat stroke, "you run the risk of permanent damage to the brain, heart, and kidneys, and you run the risk of dying because heat stroke is potentially fatal," he said.

The treatment consists of quickly cooling the patient with ice baths, packs and ventilators so that your body temperature returns to normal.

The deaths and illnesses during a heat wave mainly due to respiratory and cardiovascular disease, according to a 2015 report from the Public Health Agency of England.

How the sun can affect your health

Sunny skies and high temperatures put people at higher risk of sunburn, but it's not just a short-term nuisance.

Antony Young, professor emeritus of Experimental Photobiology at King's College London, warns that most damage caused by ultraviolet radiation is not visible to the naked eye.

Skin cancer is a delayed effect, and the condition may take 20 years to appear, according to Young.

"What we see, typically six to 24 hours later, is a sunburn. But that is just the clinical manifestation, if you wish, of a large amount of damage that begins to occur as soon as you expose your skin to the sun. "

"Because we do not repair all the damage, we receive changes in our skin DNA essentially, which are the precursors of skin cancer," said Young. "Virtually all skin cancers are caused by exposure to sunlight."

Exposure to the sun's ultraviolet rays (or tanning beds) can also accelerate the apparent age of the skin and cause deeper wrinkles.

Proper application of sunscreen is a good way to protect against the damage of UV radiation, Young said. 

A normal-sized woman sunbathing in a swimsuit would need approximately 30 grams, about 1 ounce, of sunscreen for her entire body, "which is actually quite a lot," Young said. "People usually apply a third of that, so it's about a third of the SPF they think they're getting. That's the problem, people just do not use their sunscreens well enough. "

Young also thinks that people should buy a higher SPF sunscreen to get better protection against UV rays.

What to do during a heat wave?

It is important to stay hydrated by drinking plenty of fluids. But do not fill yourself with sugary or alcoholic drinks as this would make you lose more body fluid. According to the CDC, do not drink cold water, as it could cause stomach cramps.

Make sure your drink also replaces the salt and minerals that you have lost due to sweating; Sports drinks can do that job.

Apply sunscreen on exposed skin and wear light clothing.

Make sure you enjoy the warm weather in a cool place and exercise outdoors during the coldest hours of the day: in the morning or at night.

Keep taking prescription medications, but be careful that some may reduce your tolerance to heat, warns the Public Health Agency of England.