For most healthy adults, the Department of Health and Human Services recommends at least two hours and 30 minutes a week of moderate aerobic activity or one hour and 15 minutes a week of vigorous aerobic activity — preferably spread throughout the week — and strength training exercises at least twice a week.
As a general goal, aim for at least 30 minutes of physical activity a
day. If you can't set aside that much time, try two 15-minute sessions
or three 10-minute sessions throughout the day.
Remember, though, it's OK to start slowly — especially if you haven't
been exercising regularly. You might start with five minutes a day the
first week, and then increase your time by five minutes each week until
you reach at least 30 minutes.
(info from mayoclinic.org/healthy-lifestyle)