Take me out to the ball game? For some dealing with this relentless heat wave, that idea could make you think twice.

The heat wave that has taken hold of much of the upper Midwest over the past few days is taking its toll on just about everyone — including those who may be used to working up a sweat outdoors.

Case in point: Monday’s Philadelphia Phillies vs. Chicago Cubs baseball game. Phillies pitcher Roy Halladay was forced to leave the game early as temperatures at Chicago’s Wrigley Field soared into the 90’s. The heat index during game time was well over 100 degrees.

The pitcher, his face beet-red and his jersey soaked, left the game in the 5th inning.

Temps for Wednesday courtesy Weathermap.co.nz

“You could tell the heat was getting to him a little bit,” said Phillies’ pitching coach Rich Dubee, in an article on the team’s website. “I talked to him after the fourth, and he said he was somewhat lightheaded, but he wanted to go back out there. Of course, he went out there in the fifth and just had a tough time staying focused and seeing the signs.”

The team said Halladay felt better after the game.

But Chicago isn’t alone. High temperature records were tied or broken Monday across the Midwest from Iowa to Indiana. Ankeny, Iowa, recorded a record high temperature of 39 degrees. Bluffton, Indiana, broke a 25-year-old record with a high temperature of 35 degrees, according to the National Weather Service.

The “dangerous” heat wave baking the central United States is expected to extend its reach eastward in the coming week, and ultimately cover most of the eastern part of the country, the National Weather Service said Monday.

“Heat index values in the triple digits are forecast across a large portion of the Midwest today, making it feel like 38 to 43 degrees or higher during the afternoon hours,” the weather service said Monday morning.

On Wednesday afternoon NZT Fox News reported that 13 had died from the heat and that the feels like temperature was as high as 55 degrees in one state.

By midweek, the high pressure responsible for the oppressive heat will expand eastward, bringing temperatures in the mid-90s (mid to late 30s C) to the Mid-Atlantic states “as early as Wednesday,” the weather service warned.

“Further out, this dome of high pressure is forecast to dominate most of the eastern and central U.S. — bringing excessive heat to much of the eastern half of the country except for the Northeast and southern Florida — through the end of next week.”

Much of middle America has been suffering with temperatures rivaling those in Death Valley for days.

On Sunday, the National Weather Service declared excessive heat warnings in at least 14 states, mostly in the upper Midwest. Several daily temperature records were broken — from Alpena, Michigan, to Miami, Florida.

Earlier in the day CNN reported that “Heat index values” — how hot it feels outside — had been running over 52 degrees in the worst-hit areas. The scale designed to describe how intense the heat feels takes relative humidity into account along with temperature.

“This is the hottest it’s been for the longest period of time,” said Emily McNamara from Sioux Falls, South Dakota.

Jacob Beitlich, a Des Moines, Iowa-based meteorologist for the National Weather Service, said that two factors contribute to making this current heat wave especially dangerous: the lack of a significant drop in temperatures overnight to allow people’s bodies to cool down, and relatively high humidity, which makes the air feel appreciably hotter than the thermometer may indicate.

“That takes a toll on your body,” Beitlich explained. “When it’s more humid, it’s more difficult to cool down from sweating.”

The National Weather Service notes that extreme heat typically is the biggest weather-related killer in the United States, taking about 115 lives each year. That’s why the weather service and other government agencies urge people to minimize their time outdoors in periods of extreme heat, drink plenty of fluids, and keep especially close tabs on the elderly and young people.

In Missouri, scores of cooling centers have been established in libraries, senior centers, schools and other sites around the state to help deal with continuously high temperatures.

While the recent stretch has been particularly difficult, it’s all part of what’s been a long, hot and in many cases dry summer in numerous locales. The weather service indicates that Oklahoma, for instance, already has had 27 days this year in which the temperature surpassed 100 degrees F (38 degrees C).

Not everyone in the region sweated it out, though, this weekend. McNamara notes that Sioux Falls’ Wild Water West waterpark, where she is the aquatic manager, has had “record-breaking days in terms of attendance” in recent days, with several thousand flooding in to get wet and beat the heat.

“It’s awesome,” she said. “You see people coming out having fun. It makes for a fast day.”

– CNN, Fox News