UPDATED 07/19/11 5:44 p.m.

CHICAGO (CBS) — It’s been hot and sticky for days already and being outside for long periods of time could be dangerous, but the worst is yet to come.

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Officials warn that even if you work out regularly like some runners and cyclists who were spotted along the lakefront Tuesday morning, you can still get overheated.

Emergency room doctors are ready to treat victims of heat exhaustion.

“We brought up large-scale fans to cool big patients now, in case they come in with any heat-related complaints, and we also have established misters. It’s as simple as getting a small spray, and spray it on our patients from heat-related complaints,” said Dr. Moses Lee of Stroger Hospital of Cook County.

As of 4 p.m. Tuesday, the temperature was 92 degrees at O’Hare and Midway international airports, but cooler along some parts of the lake with 81 in Waukegan and 77 in Gary, Ind.

But the heat indices are making it feel hotter than a high fever. The heat index was 110 in Joliet, 108 in Kankakee and 107 in Peru. But it was only 96 and 97 at O’Hare and Midway, respectively.

The forecast high for Tuesday is 92. Following some possible minor storms, the conditions will be muggy and on Wednesday, the temperature rises to a dangerous 97 degrees with heat indices between 105 and 115. The high for Thursday is also expected to be 97 degrees.

From 7 a.m. Wednesday to 4 a.m. Friday, the entire Chicago area is under an excessive heat warning. This denotes a prolonged period of dangerous heat.

“From Minneapolis to Chicago, Kansas City, Des Moines,” much of the Midwest is baking, and the heat will soon spread to the East Coast, says National Weather Service meteorologist Bob Oravec.

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Going to the beach might have seemed like a good idea Tuesday, but for about an hour in the middle of the day it wasn’t an option. The North Avenue and Oak Street beaches shut down just before noon due to dense fog and low visibility, and didn’t reopen until around 1 p.m. when the fog lifted.

But a day earlier when the skies were clear, beachgoers were looking for a chill in the cool waters of Lake Michigan. WBBM Newsradio 780’s Lisa Fielding caught up with a few at the 31st Street Beach.

“It’s cold, but refreshing,” said Nakea Wright, 14.

“It’s really nice here – the breeze, the water,” said Stephanie Flores of Berwyn.

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LISTEN: Newsradio 780’s Lisa Fielding reports

Everyone has their own way of cooling off. Chris Jones and his family even pitched a tent.

“Since it was hot at the house we had to come somewhere to get a cool breeze,” Jones said. “We don’t want to run and burn through the a/c, so we came out here to have some fun.”

As the hot weather will linger, many say they will be back.

“Oh, I’ll definitely be back, definitely, definitely,” said Jones.

But not everyone is finding the heat to be a day at the beach, in the literal or figurative sense.

In the Martin Luther King Plaza apartments on Madison Street near Kedzie Avenue, CBS 2’s Pamela Jones found many residents who were sitting outside on the grass with a jar of melting ice, because they had no air conditioning.

The heat index Monday made it feel like 107 degrees, but one woman said, “It feels like 207 in those houses.”

Fans are mounted in open windows, but they don’t move the air too much in this kind of heat.

“I passed out last night in all that heat. I had to go get my granddaughter’s fan,” said Lucille Davis, 81.

Even though her fan is of little use, her only choice is to sit by it.

“I had to sit right there at the window with that,” she said. “This is the best air we get.”

The Chicago Department of Family and Support Services has six cooling centers across the city, of which you can find a list here. They also open police stations and libraries for cooling.

They say about 117 people visited them on Monday

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The agency also took 45 requests for well-being checks.