High heart rate start of run

[oldgeezer]

I'm 61, 5'10", 170lbs and I run a lot. Completed one marathon, working on completed one a year for the rest of my life. I wear a heart rate monitor on every run. I run long at a comfortable pace (10 min/mile) but I don't run hard (for speed). During summer training I get up to 40 miles a week. Currently its about 25 (2 fives and a 13-15). I weight train three days a week in the winter and rest one. (Winter runs).

Last spring, and again this fall, my heart rate when I first start out goes way up (175-185) for about 5 minutes, then settles back to its normal range for the rest of the run (130-145 depending on how hard I feel like working).  What the heck is causing this high rate at the beginning of the run. I also run early in the morning (4 am) and sometimes I think its just that I don't want to get out of bed... really weird.

[oldgeezer]

I didn't mention warmups, but I spend 8 minutes on the treadmill walking before stretching and then heading out the door. I just went back and reviewed my logs (I use a  Garmin Forerunner 305 - HIGHLY RECOMMENDED) and can see all my runs on my laptop. This stopped last May, then started again in the middle of September. I wonder if it is cold weather related. The heart wants to keep the body warm... I live near Chicago and it is now in the 30-40's here at 4:00 am.

Weird.

[Flycaster305]

I'm not a medical professional, keep that in mind.  I'm exercising on a treadmill, wired up with a three lead monitor in a hospital rehab setting following a cardiac event, and I've learned that my habit of exercising at full bore with little warm up time should change.  If I don't warm up, my heart rate really spikes right after the gitgo.  I'm taking a Beta blocker so my heart rate has a 'governor' on it, but it still goes up too fast without a warmup.  If I warm up, the spike doesn't occur.  That's just a thought, I'm an  older geezer than you, though.  I notice when lifting weights and wearing my Polar heart rate monitor in the gym, exercises like a sitting arm curl really spikes the heart rate, but sitting T-bar presses which work the larger muscles of the back don't bring up the heart rate near as quickly.