Cycling Fitness / Training Advice

Go and see a doctor. Do dont ask online.

Definitely go see a doctor, it’s not easy for them to find anything of any issue, especially if it only happens during hard exercise.

I had this happen a couple of times, settling down by itself after a few minutes back to normal, for it to not happen again in the ride. Ruled out faulty HR monitor.

Took Prints of the workouts and HR to the GP who was impressed with the information and referred me for further tests.

Had a 72h ecg test, and it showed no issues, even with multiple hard rides during that time, and told to come back if it happened again.

As it happens, my neighbour is a cardiac specialist and advised that it’s probably SVT (supraventricular tachycardia), and I’ve likely had it for ages, just more visible with HR monitor wearing.
Potentially fixed by catheter ablation, but if it’s not causing me to feel ill, light headed, fainting etc, probably best to leave alone.

It only appears when I’m feeling run down, fighting a bug, or about to come down with a sickness. Happened a couple of weeks ago on a ride with a sharp climb, stopped at the top for 5 minutes for it to settle down and then didn’t show up for the rest of the ride. Day after was struck down with a horrible cold for 2 weeks.

Obviously different for everyone, but has it happened before to your knowledge?
Definitely go see a doctor.

As per everyone else, see specialist. Sudden cardiac deaths in athletes can be due to magnesium deficiency. A close friend who was exceptionally fit, working as a messenger and started having scares with his heart was referred to a specialist who had experience with this, a few days into magnesium supplementation, he was good, no further problems. Don't assume its that, get proper diagnosis, but it may be worth supplementing in high dosage in meantime.

Do you have the raw data file? I used to get spikes all the time and I'm not dead yet.

Bit late to the conversation, but as someone who has been in and out of hospital trying to diagnose the cause of my SVT (it runs in my family) then if you're worried, go to the docs. They can usually tell from a quick ECG if you have anything potentially fatal.

My experiences are that mine gets set off by sudden increases in intensity, or if I'm tired, but I'm fine if I gradually let my heartrate increase. No biggie, and as they couldn't pinpoint what was causing mine, we opted for no ablation, no drug management, just "deal with it"

When mine used to go out of rhythm badly, my HRM and ECG readings would look like an ink-covered spider having a fit on the printouts. One paramedic said he'd never seen anything like it, thought the printer was broken!