My options now seem to be:
1. Go back to my GP and demand more tests/referral to specialist.
2. Cut back on high-intensity riding.
3. Carry on regardless.
I’d welcome your advice.
If we assume that your heart-rate monitor is correct (not always the case, so it may be worth trying another one to confirm your findings), then I think this requires further attention. Various methods can be used to calculate maximum predicted heart rate, most of which give similar but slightly different estimates. Since all individuals vary, they can only ever be estimates. One rule-of-thumb formula, which has been around for many years, is ‘220 – age’. By this method, your predicted maximum rate would be 157bpm (beats per minute), well below the 220bpm you have been experiencing. Therefore, the implication would be that your 220bpm may be abnormal.
Presence of any other cardiac symptoms such as chest pain, breathlessness or dizziness would add further weight to this argument. It is also important to know whether your resting heart rate and rhythm is normal and whether you get any palpitations at other times. From your question, I believe that you have had a 24-hour ECG performed. If this was normal, I wonder whether you went cycling during the time you wore the monitor and, if so, whether your heart rate went up to 220bpm during that period?
I would encourage you to go back and talk to your GP again, taking your data with you. Your GP should consider your heart monitor readings alongside any symptoms, examination findings, and the results of tests done so far. Your doctor will then be able to advise you regarding any further cardiac investigation that may be required. In the meantime, I suggest you ease off the high-intensity riding.
Dr Matt Brooks