My heart rate fluctuates a lot between rest and work. Do I need any tests?

Hello doctor,

I am a 39-year-old male. I do daily workouts. Recently, I have been finding that my heart rate seems to be fluctuating around a lot. It could be as low as 55 when sitting down, resting, and then when I get up and walk around, it could jump to as high as 100 (I use my apple watch to monitor). Now, I know for a normal adult, the resting heart rate should and could be anywhere from 60 to 100 bpm, and for the most part, that is where it lies. But there are also times where it could go as high as 115 bpm when I am doing a simple activity such as walking or carrying groceries inside. This worries me. Also, when I drink, it seems to spike and race. Now, I know alcohol has this effect on the heart, and I only drink socially, which worries me. For instance, today, I was dropped off from the airport. I got my bags and went into the house. I checked my Apple Watch as I was walking into my apartment, and it was at 115 bpm. But then when I got inside and sat down, it went down to 60 bpm again. I went to the cardiologist, and they did a stress test and what I believe was the echocardiogram. Everything came back perfectly fine. But with these fluctuating BPM’s, I feel slightly lightheaded. And now and then, I get a slight sharp pain in my heart. Nothing constant but also happens now and then. I would like to know your thoughts on all this. I plan to make another appointment with a different cardiologist for a second opinion to see what they say. The thing that worries me the most is the high heart rate. And the fluctuation between a relatively low normal rate and a high fairy rate. I am lying down writing this, and it is at 59 bpm, but I almost feel as if I get up and start walking around, it could spike to 85 to 90 bpm. I am just not sure if that is normal.

Thank you doctor,

The lightheadedness is now and then. It is not even so much lightheaded is just a feeling of being off. Very hard to explain, actually. It does not last long either. Maybe a few seconds. Unfortunately, I cannot do an ECG on mine and upload the results. I did take a picture of the watch, though, as you can see. So you can see the fluctuation I am speaking about. I appreciate your input and that does make me feel better. I do not know why a simple activity such as just getting up to walk around is causing it to go so high. When I feel my pulse through by pressing my two fingers over my neck there does not seem to be any irregularity with the pulse. Just sometimes faster than other times. Can I still have palpitations without feeling any skipping beats?

Thank you doctor,

I had my blood work done before four months, and nothing about anemia or hyperthyroidism came up. I only have high cholesterol. So I guess based on those facts that neither of those two situations are presenting here? Also, you said you saw the fluctuations on the image I sent. Are you saying that is normal activity for a healthy heart? To me, that seemed high and worrisome.