Oh man, the Thermoregulatory Sweat Test sounds much worse than the QSART! I have a horrible heat intolerance, thank goodness they didn't give me that one lol. Some good advise I can give is to have good communication with the doctors/nurses that are giving the tests. Don't be afraid to speak up, I had to tell the nurses I wasn't feeling well and was getting worse fast, they had to abort a test and try again after relaxing a bit, one I bailed on completely (it wasn't the tests that caused my symptoms, I was already feeling horrible). Now that's far from ideal cause you want all the info you can get, but our bodies can only take so much, if you're not doing good fight it as long as you can, but listen to your body. Having someone drive you is a GREAT idea. Ask if you can do the relaxation technique class earlier, tell them you're having some anxiety or stress with all this and you think it would help. You might get surprised, the worse is they say no.