The swimming off of Carson Beach, the running in Moakley Park and the biking along Day Boulevard have been postponed as the Boston Triathlon, which had been scheduled for this weekend, is off.
"I'm, like, disappointed, because I was, like, all mentally ready for the race," said Joanna Michno.
This would have been the third Boston Triathlon for Michno, of Canterbury, New Hampshire.
She'd been preparing for months, alternating runs, swims and bike rides every day.
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"I was worried about the heat, and I would have raced anyway," she said.
But for the first time in event history, organizers say it's just too dangerous to go on because of the heat wave.
"It's going to be tough for people to be out in the sun," said Michael O'Neil, the race's director. "Not just the athletes, but the volunteers, the spectators."
There was also concern about city resources.
"When you have a heat advisory like this, I think emergency folks, Boston EMS, have their hands full just dealing with the community at large," said O'Neil. "And we didn't want to strain that at all."
Between Tuesday and Friday, Boston EMS has had more than 30 heat-related calls. Two extra ambulances are in service.
Lisa Anstee and Aimee Bloom from upstate New York say it's also too late to get their money back from their Boston hotel.
"I feel like we should have been able to do it, because we put so much time and effort into the race," said Anstee. "And I'm really disappointed."
They won't even be able to make the new date that's been selected.
"Overall, we understand that it is going to be oppressively hot," said Bloom. "We're not negating that at all, but I feel like we should have had the choice."
There are about 2,000 participants, and if they can make the new date, the various events will now take place on Aug. 20 and 21.