I was running very moderately from the beginning of the year, about three times a week, up to about 25km. I was running well and can run, at 47, near 18 minutes for a 5K. I don't race or do any long distances. I mostly stick to parkruns.
Somewhere between mid-to-late January, I noticed that when running my HR was higher than for previous-equivalent runs. Nothing drastic, but noticeable. Strava was able to keep telling me my efforts were harder than normal. I was still running okay, though. From then I started to notice the higher HR but also a drop in my VO2 Max. Over a 2-3 week period it went from about 60 down to 55. By the time I got to the beginning of March it was down to 50. During the first 6 weeks of this period I also noticed my left eye was watery and ran/teared a little whilst running.
Again in January, around the time of the increased HR, I had a couple of nights where I could hear a weird noise in my head, at night mostly. It woke me up once or twice. n fact I'd a couple of 'weird' nights. Maybe tinnitus, which I've never had.
From the beginning of March things got worse. I had abdominal pains, headaches, weird sensations in my left-hand, some tingling, even in my upper lip. Lots of 'odd' stuff. My sleep was affected.
In January I ran a 18:46 parkrun but I slowed the last 1.5k and had some abdominal pain. I didn't feel 'right'. This slowing wasn't like me at all. And I'm not a 'pusher'. Something similar happened on a training run on the 10 March, which was when I stopped running and sought medical help.
Long story cut short. I'd some bloods that fed back a low/reduced white blood count, and raised bilirubin levels (though I've had this since 2016). I had an x-ray and CT-scan, which were all okay. However, from March I was aware that even on my daily walks, my HR was elevated, sometimes by up to 30-40 beats. I could even go out and at the start see a spike to 146bpms, when I'd expect around 90.
Twice I tried to run 5K to 'see what would happen'. Twice my HR rocketed, once to 186, the highest I'd ever recorded in my life. This on an easy and short run. I didn't feel like I was dying, though it was harder than I'd expect, but my HR was way higher than it would normally be.
All of this seems to come in 'waves'. Lots of the symptoms ease a little and then pop up again, though I'd feel a general improvement. However, that's not the case with my HR. There was a week or so where I saw numbers on walks move more towards 'normal', but they then went up again a few days ago. Then, yesterday, my HR hit 166bpm on a section of a 10-minute brisk walk.
I got home and then about an hour later I went back out. I took a different Garmin (230) and a chest HRM (I normally have a wrist-based Vivoactive 3) and went out the front door again. As soon as I hit start activity, the chest HRM activated and my HR was already at 149bpms. I walked about 300m and it was up to 170. I trotted from there for about 30 or 40 metres and I was hitting 180. I stopped with, at that point, some headache, feeling sweaty etc. I went home, checked in with 111 (general medical advice) and they sent an ambulance.
An ECG said there was no signs of damage to the heart. And given that this wasn't an once-off (though it was the worst episode with my HR), this needed to go back to the GP for further investigation.
I would also add that throughout this whole period I have not had laboured breathing and even when the HR is so elevated, I'm not experiencing the kind of pounding chest and breathing that I'd kind of expect to have. I'm not saying I'm absolutely okay, but there's a mismatch between the HR and my experience of it when I'm walking or running.
I know it's a long-shot, but has anyone ever experienced similar? I'm not looking to self-diagnose or self-medicate; I'll be going back to my GP tomorrow. I just know that sometimes you have to educate yourself and fight to get the medical help you need.