Assuming you would like an answer based on scientific research:
The amount of exercise you need to stay healthy depends on your age and fitness level. Adults should aim for at least 150 minutes of moderate aerobic activity or 75 minutes of vigorous aerobic activity a week. You can also do a combination of moderate and vigorous aerobic activity. The guidelines suggest that you spread out this exercise during the course of a week.
But if you want to see health benefits beyond general maintenance, such as reduced risks for cancer, heart disease, stroke and type 2 diabetes, the guidelines recommend more – 210 minutes (3 hours and 30 minutes) a week of moderate aerobic activity OR 125 minutes (2 hours and 5 minutes) a week of high-intensity aerobic activity OR an equivalent mix of the two.