Realistically you only need to put in 25-30 minuted to get results. It really all depends on the intensity of the workout. There are many many places to find workouts. Youtube channels like Live Exercise even have a series of workouts that can be done from a chair for people who are disabled, elderly or really out of shape.
Thats what this guy says in his article too. Most of his run and workouts are only 30 minutes but are high intensity for the workouts. Runs are just the 60-65 max hr. Im in agragreement with it too. I can do a tabata workout or a trx video and feel pretty smoked by the end of it.