How the Fit Note works
Doing the right kind of work is good for your health, including if you have a health condition You don' always need to be fully recovered to go back to work, and in fact it can often help your recovery. Your fit note can help you go back to work when you're able to.
Your doctor will not automatically assess that you are not fit for work if you have a health condition. Instead, they will discuss with you how your health affects what you can do at work. They will think about your fitness for work in general rather than just your current job.
You should ask your doctor to give you practical advice in the fit note about what you can do at work, rather than simply record your health condition. You should then discuss this advice with your employer, to see if they can make any changes to help you return to work.