Well, that sucks. If you exercise especially, you need to get rid of the heat! The gym I go to has air conditioning and it is kept at ~70F (20C). If some piece of the HVAC fails, signs are posted, areas may be closed, and then it's fixed within a day or two. There's a drinking fountain for water, too. 1 year membership costs $200 US and I think the facility may be subsidized, otherwise I don't think they'd be able to offer a good deal like this.
If too much heat is a problem, try going early in the morning when it first opens. At that point the building should be the coolest it will be for the day.
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A boy and his dog can go walking
A boy and his dog sometimes talk to each other
A boy and a dog can be happy sitting down in the woods on a log
But a dog knows his boy can go wrong