I read an article about running in the heat yesterday and I came across some surprising information:
Let's say you want to go run 3 miles. If it's gosh-awful hot outside, you're probably going to run slower than you normally would. However, if you're running slower, your body isn't working as hard, even if it is 95 degrees and you're sweating like you're in a Bikram class. Doesn't that seem counterintuitive?
So, here are your options:
A. Run 2 miles instead at a fast clip.
B. Extend your run to 4 miles at a slow clip in order to get the kind of workout you would get running 3 miles under normal conditions.
In my opinion, the best thing to do is to run early in the morning or late at night when it's cooler: your risk of dehydration is decreased and you don't have to modify your workout like I mention above. I ran at 5:30 yesterday afternoon and although I only ran 2 miles, I pushed myself for the last part 1/2 mile or more because I knew I couldn't run much more!
Don't forget to hydrate!
P.S. A brief grammar rant:
The infinitive "to have" + past participle = present perfect tense
Ran = past tense of "to run"
Run = past participle of "to run"
"I have RAN 3 miles" is WRONG.
"I have RUN 3 miles" is correct.