I spend about 30 min/day on a stationary bike at the gym. As my body responds to the exercise workload, pulse goes up along with breathing rate. I check my pulse on my wrist and observe the couplet pattern: 1 strong beat followed soon by a much weaker second beat. Spacing between strong beats is 3-to-4 times the spacing between the strong and weak beats. I have seen other discussions attributing this to PVCs and think it may be relevant. I find this still curious in that the couplet pattern persists throughout most of my workout, about 30 minutes; but it eventually seems to adjust to a very regular single-beat pattern toward the end of the session or if I continue much longer than 30 min. For numbers, If I count all of the beats, my pulse runs 90-100 bpm, about what it should be for 13 mph cycling. The monitor on the bike at the gym does not detect the weak beat, so it is always off by 2. Also, although I am in this funky rhythm, I feel no weakness nor fatigue. All this has been going on for the many months since I first noticed it.
Anybody have a comment? Thanks, Rick