I am 54 and I ride my bike four or five times a week, on the road or on the turbo. I also do two weights sessions and play golf. The road sessions are 35 to 70 miles and on the turbo up to 45 minutes.

Five years ago I suffered a minor myocardial infarction. No intervention was needed, but I now take the following medication: Atenolol 12.5mg twice daily; Simvastatin 40mg daily; Aspirin 75mg daily, and Ramipril 5mg daily.

If I started using my HRM again, would my medical history and medication distort the readings and make them useless, and would trying to get into ?a zone? be dangerous?

FL, Newcastle

The Atenolol 25mgs you take twice daily belongs to the B-blocker group of drugs. One effect of this is to reduce your resting heart rate and also to reduce the maximal rate that you can raise it to during exercise, so using the standard calculations for your maximal heart rate (along the lines of 220 minus age) won?t work. You should, however, be able to use your HRM to monitor your work level taking this into account.

I assume you are prescribed Atenolol because the UK protocol for patient management following a myocardial infarction recommends it to reduce the risk of a further attack. Unfortunately it may cause some fatigue and in some individuals a tendency to wheeze. However, don?t stop taking it without medical advice.

The second part of your question is harder to answer. Any exercise carries some risk, even for those with no known heart disease. Doing no exercise following an infarction is not appropriate and the rehabilitation of heart muscle via a graduated exercise programme is now standard management, even for those who did nothing before.

I?ll assume you?ve minimised all possible risk factors by maintaining ideal weight, not smoking and keeping to the appropriate diet, in addition to your medication.

Five years have elapsed since your attack so if you had an angiogram showing no significant narrowing of your coronary arteries, it?s difficult to place limitations on your exercise level. I do, however, think this is something that you should discuss with your GP or consultant cardiologist since they will be fully informed of your circumstances.

Chris Jarvis

Doctor and adviser to British Cycling

Has been to Olympic Games and World Champs as BC?s chief medical officer