Heat waves are becoming more frequent globally. But how do we measure heat waves? We explain.

Summer isn't for another month, but Ohio is already feeling the heat.

National Weather Service heat maps show that some parts of the state will soon see temperatures approaching 90 degrees. Extreme heat waves can have negative effects on the body, including heat exhaustion and heat stroke, a life-threatening condition.

More heat-related deaths occur inside homes that lack air conditioning than outside, according to previous Cincinnati Enquirer reporting, meaning that extreme temperatures present risks that can be deadly.

Is there a difference between heat exhaustion and heat stroke? Here's what to know as temperatures heat up across Ohio.

What is heat exhaustion? What is heat stroke? What is the difference between them?

Similar to a tornado watch vs. a tornado warning, it's important to know and spot the signs and know the difference between heat exhaustion and heat stroke.

Heat exhaustion: Elevated body temperatures can cause heat exhaustion, which happens when the body can't cool itself down through sweating, according to Cleveland Clinic.

Heat stroke: Left untreated, heat exhaustion can lead to the more severe heat stroke (also known as sunstroke), which can cause permanent bodily damage or death if not addressed quickly.

Heat stroke is the most serious heat-related illness, according to the Centers for Disease Control and Prevention. It happens when the body loses the ability to cool itself. When you lose the ability to sweat, the body's temperature rises rapidly, potentially hitting 106 degrees or higher in 10 to 15 minutes.

"Heat stroke might seem like something that happens only in extreme situations, like running a marathon during a heat wave. But it can happen in the most ordinary of situations, including while you're just sitting at home on a hot day," Cleveland Clinic states.

The high temperatures this week come with high humidity, according to the National Weather Service, a combo of conditions that can lead to heat stroke.

Signs and symptoms of heat stroke

Symptoms of heat stroke, according to the CDC, include:

How to help someone experiencing heat stroke aka sunstroke

If someone is suffering from heat stroke, the CDC advises to first dial 911, then move the person to a cool, shaded area. Cool the victim using a cold bath if possible, wet their clothing with cold water or use cold, wet compresses on the head, neck, armpits or groin.

Is heat stroke preventable?

To prevent heat stroke, the Cleveland Clinic advises avoiding strenuous activity in the heat and consuming sports drinks or lightly salted water. Also, wear light, loose-fitting clothes in the heat.

If you must be outside for work or sports, gradually acclimate to the heat over several weeks. Also, you can just avoid the heat altogether by staying inside, in the air conditioning or well-ventilated areas.

What is heat exhaustion?

Heat exhaustion is the body's response to the excessive loss of water and salt, according to the CDC, usually through excessive sweating. It's most likely to affect the elderly, those with high blood pressure and people working in hot environments.

How to help someone experiencing heat exhaustion

If someone is suffering from heat exhaustion, the CDC recommends taking them to an emergency room or clinic for an evaluation or calling 911 if medical care is not available. Otherwise, remove the victim from the heat, and give them a cool drink. Remove some clothing to help them cool down, including shoes and socks. Apply cold compresses and encourage sips of cool water.

Can you prevent heat exhaustion?

To avoid heat exhaustion, the Cleveland Clinic recommends wearing loose, breathable clothing if doing physical activities outdoors in the heat and taking plenty of breaks in the shade. Also, stay hydrated. Take sips of water or a sports drink every half-hour or so. And if you know it's going to be hot, plan your activities in the morning or evening, when it's cooler.