@luvnursing52 Thank you for your comments. Apparently the lowest recorded average RHR of an athlete was 28 (and it wasn’t Usain Bolt)! Imagine.

It’s been almost 20 years since I was last an elite athlete. But having my heart learn to be effective helped in the years when I wasn’t active. My average resting heart rate stayed in the high 50’s. To suddenly have it drop so far recently with side effects of fatigue and dizziness has been a shock. Even at my fittest I didn’t go below 45.

I rechecked my smartwatch data last night and I’ve had a few days in November when my average RHR was 37!! Otherwise it’s mainly around 40-42. My doctor checked my smartwatch in real time against her equipment and it was accurate 🤷‍♀️

My BP reading in my GP appointment was normal. My bloods are good other than a Vitamin D deficiency due to malabsorption which I’m addressing with a supplement. My weight is fine.

I don’t think anything I’m doing has started this. No medications. No supplements (other than the recently started Vit D). No major exercise (walking 1 and a half hours a day with dogs who like to stop and sniff).

I’m going to ask for a Holter check and I’ve also just bought a BP monitor. I’ll start checking my weight more regularly (not just when having my PET-CT scans). I may have lost too much weight too quickly through walking and eating healthily 🤷‍♀️