Running in the heat: How to

Perhaps the only thing this winter was good for all eight months of it was making me really happy for the chance to run in the heat.  In years past, I have a great time running outside until summer and then usually find myself back in the air conditioning.  Not this year.  Almost 80* today?  No problem.

I've had a couple 'hot' runs this year.  I know people in Florida and Arizona are dying at what I call hot, but I laugh really hard at what you call cold so we're even.  Today I ran 7.5 miles and then did dynamic stretching for another 15 minutes.  In the middle of the day.  It felt hot to me, but I know there will be times this summer when that temperature feels relatively cool.  I wonder if I'll still like the heat when it's 90*?  I had a relatively long warm up and ran/walked up all of the hills on the route.  To my utter surprise, I felt great the whole time, even during the gale force winds at Lake Harriet.  What has made this wild change of heart possible? 

Helpful hints for running in hot weather:

• Heart rate monitor: Wear it.  Love it.  Listen to it.  It's nice to have a second measure of how hard I'm working (pace being the primary measure).  My heart rate creeps up in the heat, even at paces where I 'should' be able to hold a relatively low rate.
• Walk breaks: Are my friend and yours.  I find the easiest way to get my heart rate down and keep it low is with regular walk intervals.
• Longer warm ups: while counter intuitive, are important.  It seems like you'd just want to go out and get the run done as fast as possible and then get out of the heat.  In my experience, a longer warm up brings my heart rate up gently without spiking it, and I can generally last longer for the workout itself.
• Hills: I reiterate the point about warm-ups and walk breaks.