We all need to excuses but People with ADHD need it more because they need to burn off all of the excess energy to focus. What sport should I participate on? It should be they thing that you like, it can be basketball, cycling, tennis or etc. you should enjoy sport that you choose because you can’t able to focus on it, it will fell like work and people with ADHD don’t like that. Start with running and biking because you don’t need to play with others, plus it’s not competitive and it is cheap, you don’t need for a gym membership in order to run and bike, just keep it as part your daily schedule and you can really focus more.