Two weeks ago today, after an uneventful parkrun on the previous Saturday, I set out for my weekly 10k. It became clear after the first couple of k that this was not going to be a good run, so I decided to take it easy. However after 5k I felt really exhausted, so decided to take some walking breaks on the way home - that helped, but not much.
After recovering I checked my Garmin which showed I'd been in HR zone 5 for almost the whole run (peak 192!) and my resting HR continued to be high for the rest of the day. My daughter is a doctor and said 'you should see your GP'. I managed to get a telephone consultation the following day and an ECG was recommended. That showed an irregular heartbeat, so a face to face appointment was arranged for last Monday.
The diagnosis was atrial fibrillation (as suspected by my daughter) - basically an abnormal heart rhythm in the upper chambers of the heart. I've been prescribed medication to address this and an anticoagulant to reduce the risk of a stroke. I also need to have a chest x-ray and an echocardiogram (scan of the heart). It's a fairly common condition, which is more likely for people with high blood pressure and diabetes amongst other things, both of which I have. It's unlikely to have been caused by running but the scan might identify a physical cause.
As you can imagine, I was interested in how all this would affect my running! Some research on the internet suggested that as long as the irregular heartbeat had been addressed, there shouldn't be a problem. The GP's advice was that the medication should start working straight away but to leave it a few days before restarting. So early last Saturday I ventured out for an easy jog - all seemed fine and I was interested to note that my HR was 0% in zone 5! This morning I upped the pace a bit and did 5k in 30.50 with 1% zone 5. For comparison on 1 June my 5k time was 30.11 with 20% zone 5, so it is likely that I have had this condition for a while, but undiagnosed, so anyone with a similar experience may want to think about seeking medical advice.
I'm hopeful that this will resolve the issue for me, but if anything of note comes from the x-ray or scan, I'll post again.