Sure, that’s fine. We are all very busy people with jobs, kids, chores and so many other responsibilities. Inevitably, things come up and we may not be able to workout at a certain time. Therefore, its important to be flexible. Exercise whenever you have time, its convenient or have an opportunity. Sometimes you might be too tired from the days activities. In that case, you can either exercise for 15 minutes (instead of 30 minutes) or take a nap and exercise later. Thank you for posting a question.