How many minutes do you have to sustain aerobic activity to gain maximum results?

There are too many variables (such as age, training history, and the degree of cardiovascular conditioning) to answer this question. In other Words, it depends! If you are interested in maximum results from aerobic activity in the fewest minutes, consider interval training. Properly executed, it is possible in just 5 or 10 minutes of work (in other Words, excluding warm-ups and cool-downs) every other day really to increase the degree of your conditioning.