Tachycardia

[povaultrr]

I have run over 400 miles averaging 7:30 minutes per mile since August 1, 2010.  I recently bought a heart rate monitor.  For the vast majority of my runs I experience tachycardia in the range of 240 bpm to 250 bpm.  I am 31 years old and should have a maximum HR of ~185.  My resting HR is 45 bpm.  

Some background:
Run 1: 5 miles, Max HR 247, Average HR 208, 34F, pace 7:54.
Run 2: 3.7 miles, MAX HR 253, Average HR 200 (it leveled off at 160 BPM after I stopped at the 2.5 mile point) 45F
Run 3: 5 miles, Max HR 210, Average HR 165, leveled off at 165 during first six minutes, without me having to stop. 37F.

Whenever I stop, my HR always goes down with a minute or three to around 120 BPM.  I never experience chest pain or any other indicator that my heart is beating so fast.  I would think that this is due to a lack of pre-run warm ups, but the last two runs have bothered me.  Every other run (since October) that I have done had a very high HR (>230 bpm) but it went down to normal workout levels (160-180) within 3 minutes or so.  

Is the cold weather wreaking havoc on my heart by beating faster to keep me warm?  Or do I have another problem?

[kenkeith]

Yes, cold weather affects the system's cardiovascular by increasing blood pressure and heart rate....vessels constrict and blood pressure rises, and there is greater demand for oxygenated blood flow to help regulate the body temperature. This a general answer and it does not relate to any specific calculations as it pertains to any individuals and their physical condtion.

Hope this helps and thanks for sharing your experience.  Take care.