Thank you for the question and I can understand your concerns.
Firstly, its great that your investigations are normal - this is very reassuring in many aspects.
Secondly your GP has done the right thing by getting the investigations done - great job!
Murmurs in themselves may not be significant provided you are not having concurrent symptoms such as:
- Chest pain
- Dizziness/light-headedness
- Palpitations or collapse etc.
If you are fit and well, exercising regularly and have no other cardiac or family risk factors, then you can develop a murmur from changes in keeping with an athletic heart.
In terms of your exercising in the future, it would be unusual if a murmur alone caused significant problems without other symptoms or cardiac pathologies.
If you are worried, it might be worth considering a Pre-participation Screening (PPS) which provides a wholistic assessment of you as an individual - this is useful even if you have been exercising for some time.
As Dr Nandakumar mentions, an Exercise Tolerance Test (ETT) is definitely worth considering - or a more thorough assessment can be obtained with a Cardio-Pulmonary Exercise Test (CPET).
Good luck with your running and keep fit!
BW
Dr Dinesh
