I hope your doctor told you to get a kit and test your blood sugar before and after meals for a week or so to get an accurate baseline, so you aren't just going off one reading that could be higher or lower than usual.

That said, I found exercise in general and cycling specifically a major part of improving my blood sugar numbers (and my bp, cholesteral, liver function, etc etc etc.). Exercise and diet can go a LONG way towards making your healthy.