Monica, Joanne makes a good point in directing you to the ACSM position stand on Tupe 2 Diabetes. Of course, you need a physician’s okay to exercise with the client. And you need to educate yourself about the symptoms of hypo- and hyperglycemia, even though there is a very small chance that you will encounter it. It may be a good idea to have something with sugar in the workout area just to be on the safe side.
I have found that I often got a physician’s okay without any restrictions, and in that case it is a good idea to point out to the client that exercise can alter blood glucose levels, and that there may be a need to do some extra glucose testing. However, I found that many clients with type 2 diabetes are quite educated about their disease, and if it is under good control, then you do not need to get too worried about the client but just observe them as you would with anybody else.
I do a regular screening as with any other client and impose testing modifications as they present themselves. Often, but not always, people with type 2 diabetes are overweight and therefore tend to have physical limitation caused by the weight. Those usually present a greater challenge that the fact that they are diabetic.