The Department of Health recommends adults do at least 150 minutes of moderate-intensity aerobic activity, such as cycling or fast walking, every week. This doesn’t need to be done in one go, but can be broken into smaller periods. For example, you could exercise for 30 minutes a day for five days.
If you are obese and trying to lose weight, you may need to do more exercise than this. It may help to start off slowly and gradually increase the amount of exercise you do each week.