I am running a half in Chicago this weekend and the temp will probably reach the high 80s. I rarely race in the summer and haven't done much training in the heat this year. The race has an early start (8:00 a.m.) but it still be really hot, especially towards the end of the race. I train mostly at night so I am not as acclimatized to the heat as I should be. I've abandoned my hopes of setting a PR in this race, but does anyone have any tips for racing in the heat, e.g. diet modifications, supplements, singlet v. no singlet, pre-race fluid intake, sodium, etc.? I rarely race or train in the heat so this is new territory for me.