By Howard Monroe

PHILADELPHIA (CBS) — With temperatures reaching into the 90s and high humidity Tuesday, doctors are warning people to take it slow. The first thing doctors say is to hydrate and to limit your time outside during the hottest part of the day.

But that’s the opposite of what people were doing today by the Art Museum.

“It’s so humid. You start sweating as soon as you walk outside,” said walker Kelly McGovern.

A hot, humid, sweaty August afternoon; not exactly the recipe for a successful run.

“I almost went for a run. I ran for a few minutes and then realized it was too hot so I just went on a walk today,” McGovern said.

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McGovern slowed it down. Others pushed themselves even harder. They say beating the heat is a mind game.

“It’s about getting your mind together, getting your health and body together so it doesn’t matter whether there’s rain or shine, snow, hail, just get it together,” runner David Walker said.

“When I feel like doing it, heat is not usually something I worry about too much,” runner Phil Carbino said.

Others say the next big race is too important to skip a day of training.

“All these good races are coming up. Philly half, Ventura marathon, Philly marathon — it’s either now because it’s not going to happen tonight,” runner Tom Tursi said.

However, that’s exactly when doctors say you should train — either early in the morning or when the sun goes down. Coaches at Saint Joseph’s Prep changed their football practice to early morning to avoid the extreme temperatures.

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Dr. Zach Kassutto, from St. Christopher’s Hospital for Children, says heat can lead to real problems, especially for athletes.

“The things we should worry about: severe headaches, muscle cramps that won’t go away — especially if people are passing out — nausea, vomiting,” Kassutto said.

According to the Centers for Disease Control and Prevention, 600 people die from the heat each year. Kassuto says to take it easy.

“Cooling down, staying in a cool place, fans, air conditioning, water, swimming pools, sprinklers, stay in the shade. These kinds of things can be very helpful,” Kassutto said.

For those who dislike the heat, there is some good news. The average date for Philly’s last 90-degree day is Sept. 1.