Early morning run out on a bike trail. Temps in the low 60s, which was really nice. Decided to conduct an experiment and track my heart rate during the run. I have several HR monitor straps laying around the house, but they probably no longer work since I haven't used them in years. Besides I forgot about them, so I did it the old fashion way instead and counted it for 6 seconds. I started out the run a bit faster than normal at around 8 min. and started taking my HR at 20 minutes. At that point it was around 100 bpm. I was sluggish, tired, and a bit breathless as usual. I measured my heart rate every 5 minutes and it stubbornly stayed in the 100-110 range. At 35 minutes I experienced a little energy boost, which is typical for me around 25-35 minutes, making my running and breathing easier. I always thought at that point my HR must have finally climbed higher or got caught up so to speak. Took my HR at 40 minutes and I was surprised that it was still the same, even though I was running a little faster at that point. So I just ran normal the rest of the time and measured my HR every so often and all of them ended up being the same at around 90-110 bpm. I already know I have Bradycardia, but didn't think that interfered with my running. Guess I was wrong. Not sure what I can do about this other than getting a pace maker, which I'm never going to do. Perhaps some dedicated speed training might improve the link. Doubtful. Just keep experimenting I guess.