They may have insane six eight-pack abs and thigh muscles that could cut steel, but when facing down heat and dwindling hydration, CrossFit pros: they’re just like us.

At least, that was true of competitor Annie Thorisdottir at this weekend’s CrossFit Games. After suffering a "heat injury," Thorisdottir had to withdraw from Friday’s event, and made the difficult decision to leave the Games entirely on Sunday.

In multiple Instagram posts, the two-time champion explained that she “had difficulty standing and my vision was blurred” while powering through the classic Murph workout, consisting of a one mile run, 100 pull-ups, 200 push-ups, 300 squats, and ending with another mile. Thorisdottir headed to the medical tent, and after nearly three liters of saline solution she made it back to the floor that day.

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But unfortunately, it was too much for her to handle through the rest of the competition, and she made the wise decision to listen to her body instead of forcing it through the punishing final events.

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While the setting may be abnormal, anyone who’s struggled through say, a run, in 95-degree, 80%-humidity can certainly relate to Thorisdottir's dilemma. Heat injury is actually an umbrella term for the many things that can happen when exercising in the heat becomes too much, including (in order of severity) heat cramps, heat syncope (aka fainting), heat exhaustion, and the more serious heat stroke.

This week is going to be one of the hottest of the year in many parts of the country. Thorisdottir’s troubles with the heat are a good reminder to down enough water during exercise. There's no strict guideline on how much you should drink. (In fact, overdoing it on water can be dangerous, too.) In super hot weather, most people will need to break after every 15 to 20 minutes of exertion for a drink, but to stay hydrated all you really need to do is listen to your thirst.*

In really hot weather, it's also not a bad idea to have a sports drink on hand to replace electrolytes, according to the American Academy of Orthopaedic Surgeons. Heat exhaustion, for example, can be brought on by salt depletion as well as water depletion.

Despite the outcome for Thorisdottir, she stayed upbeat, promising to come back next year and regain her title as the "Fittest Woman on Earth."

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*This information has been updated.