speaking as someone who has been inside a "hot" datacenter of a few thousand servers (after a failed ac system which didn't trip the alarms for a few hours), uncomfortable does not really begin to cover it. The extremely dry, hot air was quiet difficult to breathe, and being inside for more then a couple of minutes at a time was pretty much impossible. Definitely not the same experience as sitting in a hot aisle. It has been a number of years, but I believe the thermometers read close to 100F at the time.
I wouldnt be worried about more than a few minutes. Millions of people live in climates where it gets above 100F for a significant part of the year. I used to go for hour long runs over lunch in Phoenix during the summer. Typically 100-107F. Dry/arid is actually preferable to humid ("yeah, but it's a dry heat").
I'm not saying that 100+F degree air is not livable, just relaying non-medical personal experience. I'm not doubting there were other factors, other then the heat, but it was more then just unpleasant. I've been to arizona in the summer (though I'll admit, I didn't go for long runs), but being inside that datacenter was considerably worse. Could have been the shock/drastic temperature difference though, I suppose.
