DENVER (KDVR) — With multiple days of sweltering heat, emergency room doctors in the Denver area have been working to cool people down and keep them well-hydrated.

Muscle cramping, fatigue, headache, nausea, fainting and vomiting are symptoms of heat exhaustion.

“We are seeing people that are feeling dehydrated … [feeling like] they’re having some kind of heat-related emergency,” said Dr. Eric Hill, ER physician at the Medical Center of Aurora.

On days when it’s hot enough to buckle sidewalks, doctors worry about heat exhaustion turning into heatstroke.

“If it’s dehydration, in combination with severe heat, you’re looking at your heat exhaustion and your heat stroke,” Hill explained.

Hill said heatstroke is the most extreme version of a heat-related emergency that can lead to unconsciousness and death. On average, more than 600 Americans die of heatstroke each year, according to the Journal of Emergency Medicine.

Other issues Hill and his team need to be prepared for include illnesses due to poor air quality and high UV indices.

“You can get really deep sunburns the longer you’re exposed to things … and you start getting blisters,” Hill said.

Hill told the Problem Solvers people need to make sure the sunscreen they use protects against both UVA and UVB rays.

“You have to look at the bottle and see how long [the sunscreen] lasts,” Hill said. “Realizing that if you’re going to be in the pool … some of those [sunscreens] will wash off quicker.”

Also, heat can simply stress people out. Stress can have negative consequences on the cardiovascular system.

“If you have some underlying heart disease, it very well could be that significant stress from the heat — your body is trying to cool itself down — could put more stress on your heart,” Hill said. “It could cause a heart attack.”