I wish to know if there is a possibility to reduce the hemoglobin A1c by exercises or diet. Mine is 6.9%, and although I am doing 30 minutes walk and diet, nothing changes.

I do not know how long you have been doing the activity and adhering to a diet, but the hemoglobin A1c reflects the blood glucose levels over the previous two to three months, so you need to allow at least that amount of time. Be sure to be in contact with your diabetes team and they may add an oral hypoglycemic agent to give you better control of your blood glucoses. However, keep up with the exercise and diet program.

LSF
Additional comments from Stephanie Schwartz, diabetes nurse specialist:

You do not say how long you have had diabetes or whether it is type 1 or type 2. In either case, an A1c of 6.9% reflects excellent control, and it will be very difficult to lower it without the risk of hypoglycemia.

SS