The national weather authorities in the Czech Republic, Belgium, Germany, France, Italy, Spain, and Switzerland have issued heat warnings, advising people to avoid strenuous activities during warm parts of the day, from 10 am to 4 pm, and to drink plenty of water and to stay out of the sun. There are numerous ways that your health can be put at risk during a heatwave.

After exposure to high temperatures, a lot of people will suffer minor and temporary ill-effects, such as dizziness, nausea, and fatigue, said Owen Landeg, a principal environmental public health scientist at Public Health England.

"What's important, however, is at that point we can all take steps to prevent then the more serious ill-effects of the heat," Landeg said.

This includes heat exhaustion, which happens when you become very hot after being exposed to high temperature for a long time, and your body loses water or salt. Symptoms include weakness, headaches, muscle cramps and feeling sick or faint. Heat exhaustion could lead to heatstroke, a very serious condition, according to Public Health England.

Heatstroke is less common, but it is more dangerous than heat exhaustion. It happens when your body temperature rises above 104 degrees Fahrenheit or 40 degrees Celsius. At the same time, you also experience profound changes in brain function, there are alterations in mental status or in consciousness. If this happens, you are at risk for permanent brain, heart and kidney damage and you are also at risk for death since heatstroke is fatal.

The treatment involves cooling the patient using ice baths and packs and fans to get their body temperature back to normal. Deaths and illnesses during a heatwave are due to respiratory and cardiovascular diseases. Sunny skies and high temperatures put people more at risk of getting a sunburn, but it is not just a short-term discomfort.

Antony Young, a professor of experimental photobiology at King's College London, warns that most of the damage that is caused by ultraviolet radiation is not visible. Skin cancer is a delayed effect, with the condition possibly taking at least 20 years to appear, according to Young.

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

"Because we don't repair all the damage, we get changes essentially to our DNA in the skin that are the precursors of skin cancer," Young said. "Virtually all skin cancers are caused by exposure to sunlight."

Sunbeds or ultraviolet exposure from the sun, can also accelerate the apparent age of the skin and cause more deep wrinkles. Proper sunscreen application is a good way to protect yourself against UV radiation, said Young.

Young also said that people should buy a higher SPF sunscreen to get better UV protection. It is also important to stay hydrated by drinking plenty of fluids. But, do not load up on alcoholic drinks or sugary drinks as this would make you lose more body fluid.