Forecasters say the heat index could climb into the triple digits in some parts of Ohio as hot and steamy weather covers the state.
The hottest weather so far this summer is expected to last through Friday. Ohioans will get a slight relief from the blistering temperatures when a cold front comes through on Saturday.
Dr. Eric Adkins, with the Ohio State University Wexner Medical Center, says the best option is to find some air conditioning to get into even if you don't have it at home.
"You can go out to a mall, find a grocery store, even the local library is air conditioned. You could go out and take in a good book," he said.
However, if you have to be outside, Adkins suggests you try and limit outside exposure to the morning and evening hours. The best advice is to stay hydrated, and he says there's nothing better for that than water.
"The sports drinks may have a little bit of calories, but you want to be cautious about some of those drinks that have too much sugar in them, which may promote a bit of a dehydration effect with them," Adkins said.
The sweltering temperatures Tuesday forced the IRS office in Dayton to close after experiencing air-conditioning issues.
The weather service is reminding people to never leave children and pets unattended in a car, especially in extreme weather.
(The Associated Press contributed to this story.)