Ask your doctor

I can save you the aggravation of trying to schedule an appointment, getting to the office, waiting in the paper robe to talk to him and spending $25 on your co-pay. It's right for you.

The level of exercise will vary from person to person, but you should move. Even if you have to remain seated while exercising, that's fine, just keep moving. Eventually, you will be able to get up and move.

I can't promise that your doctor will give you the same advice, though. If they are heavier than their patients, they are less likely to discuss weight. It's very possible your doctor will merely deal with the symptoms caused by excess weight and lack of exercise, rather than the causes.