As summer temperatures rise amid heatwaves, it's easy to overheat and get heatstroke, which can be life-threatening.

Let's take a look at what heatstroke is and how to prevent it.

What is heatstroke?

Heatstroke is the most serious of all heat-related illnesses. It occurs when the body's temperature rises above 40 degrees Celsius, causing organ failure, hospitalization and even death, according to the World Health Organization's website.

It occurs when the body is exposed to a high temperature and humidity environment or with high-intensity physical activity; thus, the body cannot control its temperature, said the Bureau of Medical Administration, an institution of China's National Health Commission, on Friday.

The death rate from heatstroke is extremely high, the administration said.

What are the signs of heatstroke?

According to the health regulator, common symptoms include lethargy, seizures, coma, hallucinations, inattention, memory loss, cognitive impairment and language impairment.

Other important signs include having a headache, feeling nausea, shortness of breath and increased heart rate or muscle spasms.

Who is most at risk?

People who exercise or do outdoor activities that require high levels of physical exertion are at high risk, Ai Mushan, deputy director of the emergency department of Chongqing Emergency Medical Center, told China Media Group recently in an interview.

Babies and young children, older people and people with chronic health conditions are at greater risk than others, Ai said.

How to prevent and treat heatstroke?

The health regulator recommended preventing heatstroke by staying out of the sun and avoiding physical exertion at high temperatures and humidity.

It also advised having adequate rest and drinking enough water to avoid dehydration.

If someone has heatstroke, it's important to get them to rest in a cool place and cool their skin, such as soaking them in a bathtub or spraying them with cold water, packing cool, wet towels or ice on their head, armpits and groin area and fanning their skin while it is moist. 

While cooling the patient, call an emergency center or send them to the hospital immediately to get medical help.