I am generally fit, but have had 2 episodes in 3 months where my heart rate has spiked to over 230 bpm during exercise , should i be concerned?

PAT: I would be VERY concerned about a pulse of 230 bpm, even if regular, even if "generally fit." People who feel no symptoms may have cardiovascular disease and suddenly drop dead. See a cardiologist as soon as possible.

Exercise heart rate: During exercise it is normal for the heart rate to increase. Very high heart rates may sometimes indicate a problem, but also may represent errors or artifacts in measurement. Signs that would be more concerning include rapid heart rate WITH chest discomfort, lightheadedness/fainting, or unusual shortness of breath. For personal attention, consult a cardiologist here or in person.