Getting cold after running 3+ miles????

I'm currently training for a half marathon and for the past week, I've noticed that around mile 3 my midsection feels cold to the touch and I feel a little chilled almost like goosebumps. I'm running in the Central Valley of CA and it's around 72 degrees. I sweat like crazy and find it bazar that i'd feel the chill like this after that distance.

Is this normal thermal regulation? Maybe i'm adjusting to the workout so i'm actually cooling down a little while continuing the run? 

chilled and goosebumps can be a symptom of heat exhaustion.... do you feel overheated and/or stop sweating with the chills as well when this happens?  what is your hydration plan during these runs?

mcarthur,
I do feel a little overheated (we've had horribly hot/muggy days lately) and I bring a water bottle with me on the runs with Smar****er in it. I generally consume 24 ounces on my 4 mile run and 32 ounces on my 6 miler.

I still am sweating when this happens too. It's just my belly that's cool to the touch.

Brian here from Turlock...The first few years I was cold all the time.  Yeah, you need to know the signs of dehydration...It's important.  I was working in Modesto my second year post op (standing in the shade, on a black top), it was 102 degrees and I was cold!!  I kid you not, 102 and I was cold.  It takes a few years for your body to adjust.  Like you said it is probably thermal regulation...

Our weight loss group had a trainer in one time and she said your midsection will get cold on a run because your blood is being concentrated to your working muscles, which are your legs and arms.

Thanks for the info! I'm hoping this is the case and not heat exhaustion, but i will definitely pay attention to my body for signs of it.