I go to my local Nuffield Health gym. When I started there I was very unfit and unhealthy. The first thing they do is to give you an MOT, which is (and I quote)
'a short health assessment held in Nuffield Health gyms. Using non-invasive clinical tests and a questionnaire, a highly qualified personal trainer will take your health information and use this to agree achievable health goals.
As part of your Health MOT your trainer will help you set manageable targets to achieve your goals and empower you to make the necessary changes to improve your health and fitness.'
I found this to be very important and helpful. It illuminated my shortcomings, and showed me a path to rectify them. As time passes, they will give you more MOTs to show how you have (hopefully!) improved.