Hello. I see this blog is pretty old, but I would be interested to share my experience. I have observed a rather similar behavior for me. I am 53, and in healthy conditions. The full marathon is beyond my reach (at least for now), but I am training and running for the half marathon. Every time I monitor the heart bit, the first 2min my heart rate goes up to 200, then after a couple of min it gets to 145-150, and it stays there for the whole run. I have tried two different devices, and they behave the same way. I have spoken with a cardiologist, he said it can happen because the body prepare itself for the challenge. But I think this creates a stress at the beginning of the run. I would be interested to hear from you if you still experience the same phenomenon. Thanks!
Thanks for the advice. Despite some new "better news", I am going to get a full cardiac check up, which I have never had. Yesterday I wore a cotton shirt to my local fitness center. I lathered the transmitter well with water and hopped on the treadmill. I took it easy the first 1.2 miles (5.1 mph) and then increased the pace every 1/10th mile until I was running 8 mph (7:30 pace). During the entire 1.2 miles, my pulse ranged between 131 and 132, except for a brief period of increase at the beginning. My pulse followed a steady curve on the graph to a maximum of 168 (too fast!). Then I cooled down at 6 mph where my pulse dropped to 148 and remained fairly steady. There was nothing unusual at all recorded on my Garmin 305, which is only two weeks old. I am starting to believe that it is due to not adequately lubricating the transmitter. Hopefully that is the case.
I have also noticed a high heart rate on my Polar monitor during the beginning of a run. I think this is due to poor conduction of the transmitter. You can purchase conductive gel from a sports catalog that sells heart monitors which should prevent this. This increase is roughly 1/2 the actual rate high which sounds close to what you are seeing. Unfortunately, in my case I see very high rates after a period of exercise which is AFIB unsustained. A 24 hour Holter monitor test will confirm a normal heart function. I pushed as hard as I could on an exercise bike to see some very interesting data that frightened my primary care physician and led to a lot of additional testing. I think a stess test or Holter with exercise would not be a bad idea for an older runner to validate proper heart function.
I have 4 friends, all over 45 years old who have also developed arrhythmia and somewhere I read that endurance athletes with resting low heart rates are 5.5 times more likely to develop arrhythmia problems. Hope you don't join this club.
My 150 plus heart rate during competition is normal for me. As a matter of fact, I can sustain 160s. It's low compared to when I was younger. Of course, I'm slower. When you do aerobic conditioning for over 30 years, it is not unusual to be able to sustain a high heart rate during continuous physical exertion. As long as my breathing is relaxed and rythmic, I am ok. However, the 180 to 200 heart rates during the first mile when I feel like I'm not pushing it very hard during the first mile is disturbing. Of course, I have discovered that this has been going on for some time, and I'm not dead yet and have never had any symptoms at all. Regarding a second wind after the first mile, I think I can help you with that. When you first start out, your body is adjusting. Once you are warmed up, you should feel better, providing you don't go out too fast. If you have labored breathing the first mile, start out slower and ease into your run. If you do this, your pace should automatically get faster after about 1/2 mile or so. Thus, your second mile will be faster without even trying.
Well your physical condition is far beyond anything I can imagine, but at age 62 you upper heart rate numbers look alarming to me. For that reason alone I suggest you discuss your training and competition experience with a Cardiologist.
That said, I'd say "second wind". I have never run more than 3 miles, but even with that I have pushed myself hard enough to "feel" the "second wind" effect, that is a feeling of refreshment and more energy and wind. I have never noted a drop in HR,but then I wasn't looking either.
What do you think about the human body getting a "second wind" effect after the first mile or two in a run? I mean it is something very normal, at least for those who put out that level of physical exertion.