Resting heart rate around 53 after shower 120. Goes back to 60s shortly after. PCP says not a concern. Is this "normal"? Terrified!!!

Heart rate. As long as you don't have other signs or symptoms I would agree this sounds normal. Hot water dilates blood vessels and causes HR to increase. The degree of elevation depends upon vascular tone and degree of hydration. If these episodes were captured on hotter then the answer is definitive.
Terror. Don't be terrified. This heart rate response is fine. Listen to your doc who knows your condition. No one out here knows you as well.

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My resting heart rate is about 60bpm but I can feel the pumping in my ears, neck, shoulders and back. Is this normal as an athlete?

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