You do not have to kill yourself from running a lot of kilometers or lift heavy dumbells etc., but you should have some sort of moderate physical activity in your everyday life. If you're looking to shed a few pounds fast, do a higher-level intensity workout For example, go on a walk at a brisk pace for an hour. Or, you can jog and set certain intervals to sprint during that hour. Make sure you're not in severe pain during your workout. You can also you a workout app to help you know the right workout and how to do it well, just take is step by step until you're able to do more.